diff --git a/package.json b/package.json
index 842016c..984167d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@clober/v2-sdk",
-  "version": "0.0.60.dev",
+  "version": "0.0.60",
   "description": "🛠 An SDK for building applications on top of Clober V2",
   "files": [
     "dist"
diff --git a/src/apis/market.ts b/src/apis/market.ts
index f1c2058..a006d41 100644
--- a/src/apis/market.ts
+++ b/src/apis/market.ts
@@ -53,7 +53,7 @@ const getBook = async (
     const {
       data: { book },
     } = await fetchBookFromSubgraph(chainId, bookId.toString())
-    new Book({
+    return new Book({
       chainId,
       id: bookId,
       base: baseCurrency,