diff --git a/crud.py b/crud.py
new file mode 100644
index 00000000..91f0abc0
--- /dev/null
+++ b/crud.py
@@ -0,0 +1,55 @@
+from sqlalchemy.orm import Session
+
+import models
+import schemas
+
+
+def get_author(db: Session, author_id: int):
+    return db.query(models.Author).filter(models.Author.id == author_id).first()
+
+
+def get_author_by_name(db: Session, name: str):
+    return db.query(models.Author).filter(models.Author.name == name).first()
+
+
+def get_authors(db: Session, skip: int = 0, limit: int = 100):
+    return db.query(models.Author).offset(skip).limit(limit).all()
+
+
+def create_author(db: Session, author: schemas.AuthorCreate):
+    db_author = models.Author(name=author.name, bio=author.bio)
+    db.add(db_author)
+    db.commit()
+    db.refresh(db_author)
+    return db_author
+
+
+def get_book(db: Session, book_id: int):
+    return db.query(models.Book).filter(models.Book.id == book_id).first()
+
+
+def get_books(db: Session, skip: int = 0, limit: int = 100):
+    return db.query(models.Book).offset(skip).limit(limit).all()
+
+
+def get_books_by_author(db: Session, author_id: int, skip: int = 0, limit: int = 100):
+    return (
+        db.query(models.Book)
+        .filter(models.Book.author_id == author_id)
+        .offset(skip)
+        .limit(limit)
+        .all()
+    )
+
+
+def create_book(db: Session, book: schemas.BookCreate, author_id: int):
+    db_book = models.Book(
+        title=book.title,
+        summary=book.summary,
+        publication_date=book.publication_date,
+        author_id=author_id,
+    )
+    db.add(db_book)
+    db.commit()
+    db.refresh(db_book)
+    return db_book
diff --git a/database.py b/database.py
new file mode 100644
index 00000000..ae8ff98a
--- /dev/null
+++ b/database.py
@@ -0,0 +1,13 @@
+from sqlalchemy import create_engine
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import sessionmaker
+
+SQLALCHEMY_DATABASE_URL = "sqlite:///./library.db"
+
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL, connect_args={"check_same_thread": False}
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+Base = declarative_base()
diff --git a/main.py b/main.py
new file mode 100644
index 00000000..568429a6
--- /dev/null
+++ b/main.py
@@ -0,0 +1,64 @@
+from fastapi import Depends, FastAPI, HTTPException, Query
+from sqlalchemy.orm import Session
+
+import crud
+import models
+import schemas
+from database import SessionLocal, engine
+
+models.Base.metadata.create_all(bind=engine)
+
+app = FastAPI(title="Library Management API")
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+@app.post("/authors/", response_model=schemas.AuthorRead, status_code=201)
+def create_author(author: schemas.AuthorCreate, db: Session = Depends(get_db)):
+    existing = crud.get_author_by_name(db, name=author.name)
+    if existing:
+        raise HTTPException(status_code=400, detail="Author with this name already exists")
+    return crud.create_author(db=db, author=author)
+
+
+@app.get("/authors/", response_model=list[schemas.AuthorRead])
+def read_authors(
+    skip: int = Query(0, ge=0), limit: int = Query(100, ge=1), db: Session = Depends(get_db)
+):
+    return crud.get_authors(db, skip=skip, limit=limit)
+
+
+@app.get("/authors/{author_id}", response_model=schemas.AuthorRead)
+def read_author(author_id: int, db: Session = Depends(get_db)):
+    db_author = crud.get_author(db, author_id=author_id)
+    if db_author is None:
+        raise HTTPException(status_code=404, detail="Author not found")
+    return db_author
+
+
+@app.post("/authors/{author_id}/books/", response_model=schemas.BookRead, status_code=201)
+def create_book_for_author(
+    author_id: int, book: schemas.BookCreate, db: Session = Depends(get_db)
+):
+    db_author = crud.get_author(db, author_id=author_id)
+    if db_author is None:
+        raise HTTPException(status_code=404, detail="Author not found")
+    return crud.create_book(db=db, book=book, author_id=author_id)
+
+
+@app.get("/books/", response_model=list[schemas.BookRead])
+def read_books(
+    author_id: int | None = Query(None, alias="authorId"),
+    skip: int = Query(0, ge=0),
+    limit: int = Query(100, ge=1),
+    db: Session = Depends(get_db),
+):
+    if author_id is not None:
+        return crud.get_books_by_author(db, author_id=author_id, skip=skip, limit=limit)
+    return crud.get_books(db, skip=skip, limit=limit)
diff --git a/models.py b/models.py
new file mode 100644
index 00000000..2ac13548
--- /dev/null
+++ b/models.py
@@ -0,0 +1,26 @@
+from sqlalchemy import Column, Date, ForeignKey, Integer, String
+from sqlalchemy.orm import relationship
+
+from database import Base
+
+
+class Author(Base):
+    __tablename__ = "authors"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, unique=True, nullable=False, index=True)
+    bio = Column(String, nullable=True)
+
+    books = relationship("Book", back_populates="author", cascade="all, delete-orphan")
+
+
+class Book(Base):
+    __tablename__ = "books"
+
+    id = Column(Integer, primary_key=True, index=True)
+    title = Column(String, nullable=False, index=True)
+    summary = Column(String, nullable=True)
+    publication_date = Column(Date, nullable=False)
+    author_id = Column(Integer, ForeignKey("authors.id"), nullable=False)
+
+    author = relationship("Author", back_populates="books")
diff --git a/schemas.py b/schemas.py
new file mode 100644
index 00000000..5947757e
--- /dev/null
+++ b/schemas.py
@@ -0,0 +1,39 @@
+from datetime import date
+from typing import List, Optional
+
+from pydantic import BaseModel
+
+
+class BookBase(BaseModel):
+    title: str
+    summary: Optional[str] = None
+    publication_date: date
+
+
+class BookCreate(BookBase):
+    pass
+
+
+class BookRead(BookBase):
+    id: int
+    author_id: int
+
+    class Config:
+        orm_mode = True
+
+
+class AuthorBase(BaseModel):
+    name: str
+    bio: Optional[str] = None
+
+
+class AuthorCreate(AuthorBase):
+    pass
+
+
+class AuthorRead(AuthorBase):
+    id: int
+    books: List[BookRead] = []
+
+    class Config:
+        orm_mode = True