diff --git a/app/build.gradle b/app/build.gradle
index 217a492..3f4a8b6 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -1,6 +1,7 @@
 plugins {
     id 'com.android.application'
     id 'kotlin-android'
+    id 'kotlin-kapt'
     id 'org.jetbrains.kotlin.android'
 }
 
@@ -102,6 +103,14 @@ dependencies {
     implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
     implementation 'com.google.code.gson:gson:2.8.6'
 
+    // Room
+    implementation "androidx.room:room-runtime:2.3.0"
+    implementation "androidx.room:room-ktx:2.3.0"
+    kapt "androidx.room:room-compiler:2.3.0"
+
+    // Paging
+    implementation "androidx.paging:paging-runtime-ktx:3.0.0"
+
     // Test
     testImplementation 'junit:junit:4.13.2'
     androidTestImplementation "androidx.compose.ui:ui-test-junit4:1.0.0-beta06"
diff --git a/app/src/main/java/com/pixelized/biblib/BibLibApplication.kt b/app/src/main/java/com/pixelized/biblib/BibLibApplication.kt
index 83358ec..663c5da 100644
--- a/app/src/main/java/com/pixelized/biblib/BibLibApplication.kt
+++ b/app/src/main/java/com/pixelized/biblib/BibLibApplication.kt
@@ -3,8 +3,10 @@ package com.pixelized.biblib
 import android.app.Application
 import android.content.Context
 import android.content.SharedPreferences
+import androidx.room.Room
 import com.google.gson.Gson
 import com.google.gson.GsonBuilder
+import com.pixelized.biblib.database.BibLibDatabase
 import com.pixelized.biblib.network.client.BibLibClient
 import com.pixelized.biblib.network.client.IBibLibClient
 import com.pixelized.biblib.repository.apiCache.APICacheRepository
@@ -21,18 +23,23 @@ class BibLibApplication : Application() {
     override fun onCreate() {
         super.onCreate()
 
+        // Android.
+        Bob[BibLibDatabase::class] =
+            Room.databaseBuilder(this, BibLibDatabase::class.java, BibLibDatabase.DATABASE_NAME)
+                .build()
         Bob[SharedPreferences::class] = getSharedPreferences(SHARED_PREF, Context.MODE_PRIVATE)
+        // Web service.
         Bob[Gson::class] = GsonBuilder().create()
-        Bob[BitmapCache::class] = BitmapCache(this)
-
         Bob[IBibLibClient::class] = BibLibClient()
-
+        // Bitmap cache.
+        Bob[BitmapCache::class] = BitmapCache(this)
+        // Repositories.
         Bob[IGoogleSingInRepository::class] = GoogleSingInRepository(this)
         Bob[ICredentialRepository::class] = CredentialRepository()
         Bob[IAPICacheRepository::class] = APICacheRepository()
     }
 
     companion object {
-        const val SHARED_PREF = "BIB_LIB_SHARED_PREF"
+        private const val SHARED_PREF = "BIB_LIB_SHARED_PREF"
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/BibLibDatabase.kt b/app/src/main/java/com/pixelized/biblib/database/BibLibDatabase.kt
new file mode 100644
index 0000000..df852ac
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/BibLibDatabase.kt
@@ -0,0 +1,37 @@
+package com.pixelized.biblib.database
+
+import androidx.room.Database
+import androidx.room.RoomDatabase
+import androidx.room.TypeConverters
+import com.pixelized.biblib.database.converter.DateConverter
+import com.pixelized.biblib.database.crossref.BookAuthorCrossRef
+import com.pixelized.biblib.database.crossref.BookGenreCrossRef
+import com.pixelized.biblib.database.dao.*
+import com.pixelized.biblib.database.data.*
+
+@Database(
+    entities = [
+        AuthorDbo::class,
+        BookDbo::class,
+        GenreDbo::class,
+        LanguageDbo::class,
+        SeriesDbo::class,
+        BookAuthorCrossRef::class,
+        BookGenreCrossRef::class,
+    ],
+    version = BibLibDatabase.VERSION
+)
+@TypeConverters(DateConverter::class)
+abstract class BibLibDatabase : RoomDatabase() {
+
+    abstract fun authorDao(): AuthorDao
+    abstract fun bookDao(): BookDao
+    abstract fun genreDao(): GenreDao
+    abstract fun languageDao(): LanguageDao
+    abstract fun seriesDao(): SeriesDao
+
+    companion object {
+        const val VERSION = 1
+        const val DATABASE_NAME = "BibLibDataBase"
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/converter/DateConverter.kt b/app/src/main/java/com/pixelized/biblib/database/converter/DateConverter.kt
new file mode 100644
index 0000000..a7ce6ec
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/converter/DateConverter.kt
@@ -0,0 +1,12 @@
+package com.pixelized.biblib.database.converter
+
+import androidx.room.TypeConverter
+import java.util.*
+
+class DateConverter {
+    @TypeConverter
+    fun fromTimestamp(value: Long?): Date? = value?.let { Date(it) }
+
+    @TypeConverter
+    fun dateToTimestamp(date: Date?): Long? = date?.time
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/crossref/BookAuthorCrossRef.kt b/app/src/main/java/com/pixelized/biblib/database/crossref/BookAuthorCrossRef.kt
new file mode 100644
index 0000000..10e588a
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/crossref/BookAuthorCrossRef.kt
@@ -0,0 +1,14 @@
+package com.pixelized.biblib.database.crossref
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import com.pixelized.biblib.database.data.AuthorDbo
+import com.pixelized.biblib.database.data.BookDbo
+
+@Entity(primaryKeys = [BookDbo.ID, AuthorDbo.ID])
+data class BookAuthorCrossRef(
+    @ColumnInfo(name = BookDbo.ID)
+    val bookId: String,
+    @ColumnInfo(name = AuthorDbo.ID)
+    val authorId: String
+)
diff --git a/app/src/main/java/com/pixelized/biblib/database/crossref/BookGenreCrossRef.kt b/app/src/main/java/com/pixelized/biblib/database/crossref/BookGenreCrossRef.kt
new file mode 100644
index 0000000..478532c
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/crossref/BookGenreCrossRef.kt
@@ -0,0 +1,14 @@
+package com.pixelized.biblib.database.crossref
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import com.pixelized.biblib.database.data.BookDbo
+import com.pixelized.biblib.database.data.GenreDbo
+
+@Entity(primaryKeys = [BookDbo.ID, GenreDbo.ID])
+data class BookGenreCrossRef(
+    @ColumnInfo(name = BookDbo.ID)
+    val bookId: String,
+    @ColumnInfo(name = GenreDbo.ID)
+    val genreId: String
+)
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/dao/AuthorDao.kt b/app/src/main/java/com/pixelized/biblib/database/dao/AuthorDao.kt
new file mode 100644
index 0000000..7428d69
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/dao/AuthorDao.kt
@@ -0,0 +1,16 @@
+package com.pixelized.biblib.database.dao
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import com.pixelized.biblib.database.data.AuthorDbo
+
+@Dao
+interface AuthorDao {
+    @Query("SELECT * FROM ${AuthorDbo.TABLE} WHERE ${AuthorDbo.ID} LIKE :id")
+    fun get(id: String?): AuthorDbo?
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    fun insert(vararg authors: AuthorDbo)
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/dao/BookDao.kt b/app/src/main/java/com/pixelized/biblib/database/dao/BookDao.kt
new file mode 100644
index 0000000..5a6501d
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/dao/BookDao.kt
@@ -0,0 +1,18 @@
+package com.pixelized.biblib.database.dao
+
+import androidx.room.*
+import com.pixelized.biblib.database.data.BookDbo
+import com.pixelized.biblib.database.relation.BookRelation
+
+@Dao
+interface BookDao {
+    @Transaction
+    @Query("SELECT * FROM ${BookDbo.TABLE}")
+    fun getAll(): List<BookRelation>
+
+    @Insert
+    fun update(vararg books: BookDbo)
+
+    @Delete
+    fun delete(book: BookDbo)
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/dao/GenreDao.kt b/app/src/main/java/com/pixelized/biblib/database/dao/GenreDao.kt
new file mode 100644
index 0000000..4d97df4
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/dao/GenreDao.kt
@@ -0,0 +1,16 @@
+package com.pixelized.biblib.database.dao
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import com.pixelized.biblib.database.data.GenreDbo
+
+@Dao
+interface GenreDao {
+    @Query("SELECT * FROM ${GenreDbo.TABLE} WHERE ${GenreDbo.ID} LIKE :id")
+    fun get(id: String?): GenreDbo?
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    fun insert(vararg genres: GenreDbo)
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/dao/LanguageDao.kt b/app/src/main/java/com/pixelized/biblib/database/dao/LanguageDao.kt
new file mode 100644
index 0000000..b427c65
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/dao/LanguageDao.kt
@@ -0,0 +1,16 @@
+package com.pixelized.biblib.database.dao
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import com.pixelized.biblib.database.data.LanguageDbo
+
+@Dao
+interface LanguageDao {
+    @Query("SELECT * FROM ${LanguageDbo.TABLE} WHERE ${LanguageDbo.ID} LIKE :id")
+    fun get(id: String?): LanguageDbo?
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    fun insert(vararg languages: LanguageDbo)
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/dao/SeriesDao.kt b/app/src/main/java/com/pixelized/biblib/database/dao/SeriesDao.kt
new file mode 100644
index 0000000..7eb2450
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/dao/SeriesDao.kt
@@ -0,0 +1,16 @@
+package com.pixelized.biblib.database.dao
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import com.pixelized.biblib.database.data.SeriesDbo
+
+@Dao
+interface SeriesDao {
+    @Query("SELECT * FROM ${SeriesDbo.TABLE} WHERE ${SeriesDbo.ID} LIKE :id")
+    fun get(id: String?): SeriesDbo?
+
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
+    fun insert(vararg series: SeriesDbo)
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/data/AuthorDbo.kt b/app/src/main/java/com/pixelized/biblib/database/data/AuthorDbo.kt
new file mode 100644
index 0000000..fa91a63
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/data/AuthorDbo.kt
@@ -0,0 +1,23 @@
+package com.pixelized.biblib.database.data
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = AuthorDbo.TABLE)
+data class AuthorDbo(
+    @PrimaryKey
+    @ColumnInfo(name = ID)
+    val id: String,
+    @ColumnInfo(name = NAME)
+    val name: String,
+    @ColumnInfo(name = SORT)
+    val sort: String,
+) {
+    companion object {
+        const val TABLE = "AUTHOR"
+        const val ID = "${TABLE}_ID"
+        const val NAME = "${TABLE}_NAME"
+        const val SORT = "${TABLE}_SORT"
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/data/BookDbo.kt b/app/src/main/java/com/pixelized/biblib/database/data/BookDbo.kt
new file mode 100644
index 0000000..fbabe9c
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/data/BookDbo.kt
@@ -0,0 +1,58 @@
+package com.pixelized.biblib.database.data
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+import java.util.*
+
+@Entity(tableName = BookDbo.TABLE)
+data class BookDbo(
+    @PrimaryKey
+    @ColumnInfo(name = ID)
+    val id: Int,
+    @ColumnInfo(name = TITLE)
+    val title: String,
+    @ColumnInfo(name = SORT)
+    val sort: String,
+    @ColumnInfo(name = HAVE_COVER)
+    val haveCover: Boolean,
+    @ColumnInfo(name = RELEASE_DATE)
+    val releaseDate: Date,
+    @ColumnInfo(name = LANGUAGE_ID)
+    val language: String? = null,       // one-to-many
+    @ColumnInfo(name = RATING)
+    val rating: Int? = null,
+    // details
+    @ColumnInfo(name = SERIES_ID)
+    val series: String? = null,         // one-to-many
+    @ColumnInfo(name = SYNOPSIS)
+    val synopsis: String? = null,
+    // source
+    @ColumnInfo(name = IS_NEW)
+    val isNew: Boolean = false,
+) {
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is BookDbo) return false
+        if (id != other.id) return false
+        return true
+    }
+
+    override fun hashCode(): Int {
+        return id
+    }
+
+    companion object {
+        const val TABLE = "BOOK"
+        const val ID = "${TABLE}_ID"
+        const val TITLE = "${TABLE}_TITLE"
+        const val SORT = "${TABLE}_SORT"
+        const val HAVE_COVER = "${TABLE}_HAVE_COVER"
+        const val RELEASE_DATE = "${TABLE}_RELEASE_DATE"
+        const val LANGUAGE_ID = "${TABLE}_LANGUAGE_ID"
+        const val RATING = "${TABLE}_RATING"
+        const val SERIES_ID = "${TABLE}_SERIES_ID"
+        const val SYNOPSIS = "${TABLE}_SYNOPSIS"
+        const val IS_NEW = "${TABLE}_ISNEW"
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/data/GenreDbo.kt b/app/src/main/java/com/pixelized/biblib/database/data/GenreDbo.kt
new file mode 100644
index 0000000..2ec091f
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/data/GenreDbo.kt
@@ -0,0 +1,20 @@
+package com.pixelized.biblib.database.data
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = GenreDbo.TABLE)
+data class GenreDbo(
+    @PrimaryKey
+    @ColumnInfo(name = ID)
+    val id: String,
+    @ColumnInfo(name = NAME)
+    val name: String,
+) {
+    companion object {
+        const val TABLE = "GENRE"
+        const val ID = "${TABLE}_ID"
+        const val NAME = "${TABLE}_NAME"
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/data/LanguageDbo.kt b/app/src/main/java/com/pixelized/biblib/database/data/LanguageDbo.kt
new file mode 100644
index 0000000..5f58a18
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/data/LanguageDbo.kt
@@ -0,0 +1,21 @@
+package com.pixelized.biblib.database.data
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = LanguageDbo.TABLE)
+data class LanguageDbo(
+    @PrimaryKey
+    @ColumnInfo(name = ID)
+    val id: String,
+    @ColumnInfo(name = NAME)
+    val code: String,
+) {
+    companion object {
+        const val TABLE = "LANGUAGE"
+        const val ID = "${TABLE}_ID"
+        const val NAME = "${TABLE}_NAME"
+    }
+}
+
diff --git a/app/src/main/java/com/pixelized/biblib/database/data/SeriesDbo.kt b/app/src/main/java/com/pixelized/biblib/database/data/SeriesDbo.kt
new file mode 100644
index 0000000..cbdc57c
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/data/SeriesDbo.kt
@@ -0,0 +1,26 @@
+package com.pixelized.biblib.database.data
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = SeriesDbo.TABLE)
+data class SeriesDbo(
+    @PrimaryKey
+    @ColumnInfo(name = ID)
+    val id: String,
+    @ColumnInfo(name = NAME)
+    val name: String,
+    @ColumnInfo(name = SORT)
+    val sort: String,
+    @ColumnInfo(name = INDEX)
+    val index: Int?,
+) {
+    companion object {
+        const val TABLE = "SERIES"
+        const val ID = "${TABLE}_ID"
+        const val NAME = "${TABLE}_NAME"
+        const val SORT = "${TABLE}_SORT"
+        const val INDEX = "${TABLE}_INDEX"
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/pixelized/biblib/database/relation/BookRelation.kt b/app/src/main/java/com/pixelized/biblib/database/relation/BookRelation.kt
new file mode 100644
index 0000000..0a50a66
--- /dev/null
+++ b/app/src/main/java/com/pixelized/biblib/database/relation/BookRelation.kt
@@ -0,0 +1,35 @@
+package com.pixelized.biblib.database.relation
+
+import androidx.room.Embedded
+import androidx.room.Junction
+import androidx.room.Relation
+import com.pixelized.biblib.database.crossref.BookAuthorCrossRef
+import com.pixelized.biblib.database.crossref.BookGenreCrossRef
+import com.pixelized.biblib.database.data.*
+
+data class BookRelation(
+    @Embedded
+    val bookDbo: BookDbo,
+    @Relation(
+        parentColumn = BookDbo.ID,
+        entityColumn = AuthorDbo.ID,
+        associateBy = Junction(BookAuthorCrossRef::class)
+    )
+    val authors: List<AuthorDbo>,
+    @Relation(
+        parentColumn = BookDbo.ID,
+        entityColumn = GenreDbo.ID,
+        associateBy = Junction(BookGenreCrossRef::class)
+    )
+    val genres: List<GenreDbo>,
+    @Relation(
+        parentColumn = BookDbo.LANGUAGE_ID,
+        entityColumn = LanguageDbo.ID
+    )
+    val language: LanguageDbo,
+    @Relation(
+        parentColumn = BookDbo.SERIES_ID,
+        entityColumn = SeriesDbo.ID
+    )
+    val series: SeriesDbo,
+)
\ No newline at end of file