diff --git a/models/book.py b/models/book.py
index 5163d00..10e9959 100644
--- a/models/book.py
+++ b/models/book.py
@@ -11,12 +11,13 @@ class Book(Base):
     title = Column(String, nullable=False, index=True)
     description = Column(String)
     isbn = Column(String, unique=True)
-    publication_year = Column(Integer)
     author_id = Column(String, ForeignKey("authors.id"), nullable=False)
+    publication_year = Column(Integer)
+    pages = Column(Integer)
+    genre = Column(String)
+    publisher = Column(String)
     
-    # Relationships
-    author = relationship("Author", back_populates="books")
-    
-    # Timestamps
     created_at = Column(DateTime, default=func.now())
-    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())
\ No newline at end of file
+    updated_at = Column(DateTime, default=func.now(), onupdate=func.now())
+    
+    author = relationship("Author", back_populates="books")
\ No newline at end of file