diff --git a/app.js b/app.js
index 187fcae..e4361f6 100644
--- a/app.js
+++ b/app.js
@@ -14,3 +14,97 @@ const books = [
   { author: "Aldous Huxley", title: "Animal Farm", id: 9 },
   { author: "Aldous Huxley", title: "Brave New World", id: 10 },
 ];
+
+function Library(name, books) {
+  this.name = name;
+  this.books = books;
+
+  this.addBook = (title, author, id) => {
+    const newBook = new Book(title, author, id);
+
+    this.books.push(newBook);
+  };
+
+  this.removeBook = (id) => {
+    this.books = this.books.filter((book) => book.id !== id);
+  };
+
+  this.checkOutBook = (bookId, patron) => {
+    this.books = this.books.map((book) => {
+      if (book.id === bookId) {
+        const { title, author, id } = book;
+
+        const status = new BookStatus(true, patron);
+
+        return new Book(title, author, id, status);
+      } else {
+        return book;
+      }
+    });
+  };
+
+  this.checkInBook = (bookId) => {
+    this.books = this.books.map((book) => {
+      if (book.id === bookId) {
+        const { title, author, id } = book;
+
+        const status = new BookStatus();
+
+        return new Book(title, author, id, status);
+      } else {
+        return book;
+      }
+    });
+  };
+
+  this.getBookById = (id) => {
+    return this.books.find((book) => book.id === id);
+  };
+}
+
+function Book(title, author, id, status) {
+  this.title = title;
+  this.author = author;
+  this.id = id;
+  this.status = status;
+}
+
+function Patron(name, id) {
+  this.name = name;
+  this.id = id;
+}
+
+function BookStatus(checkedOut = false, patron = null) {
+  this.checkedOut = checkedOut;
+  this.patron = patron;
+}
+
+const library = new Library("Central Library", books);
+
+// Adding new books
+library.addBook("The Alchemist", "Paulo Coelho", 11);
+library.addBook("The Da Vinci Code", "Dan Brown", 12);
+
+// Removing a book
+library.removeBook(5);
+
+// Creating a new patron
+const patron = new Patron("John Smith", 1);
+
+// Checking out a book for the patron
+library.checkOutBook(3, patron);
+
+// Logging the book checked out by the patron
+const checkedOutBook = library.getBookById(3);
+console.log(
+  `bookTitle: ${checkedOutBook.title}, checkedOutBy: ${checkedOutBook.status.patron.name}`
+);
+
+// Checking the book back in
+library.checkInBook(3);
+
+// Logging the book checked in by the patron
+const checkedInBook = library.getBookById(3);
+console.log(
+  `bookTitle: ${checkedInBook.title}, checkedOut: ${checkedInBook.status.checkedOut}`
+);
\ No newline at end of file