diff --git a/src/objects.ts b/src/objects.ts
index ef6298f..2690f35 100644
--- a/src/objects.ts
+++ b/src/objects.ts
@@ -26,9 +26,13 @@ function createBook(
   publishedYear: number,
   genre: string
 ): Book {
-  // write your code here...
-
-  return {} as Book; // replace "{} as Book" with what you see is fit
+  let book: Book = {
+    title: title,
+    author: author,
+    publishedYear: publishedYear,
+    genre: genre,
+  };
+  return book;
 }
 
 // DO NOT CHANGE THE LINE OF CODE BELOW (you can use it for testing your code)
@@ -49,9 +53,7 @@ const book = createBook(
  *   // => "Hitchhiker's Guide to The Galaxy 1965"
  */
 function printBookTitleAndYear(book: Book): string {
-  // write your code here...
-
-  return ""; // replace empty string with what you see is fit
+  return book.title + " " + book["publishedYear"];
 }
 
 /**
@@ -65,7 +67,7 @@ function printBookTitleAndYear(book: Book): string {
  *   // => { title: "Hitchhiker's Guide to The Galaxy", author: "Douglas Adams", publishedYear: 1965, genre: "Sci-Fi", pageCount: 320 }
  */
 function addPageCount(book: Book, pageCount: number): Book {
-  // write your code here...
+  book.pageCount = pageCount;
 
   return book;
 }
@@ -87,7 +89,7 @@ function addPageCount(book: Book, pageCount: number): Book {
  *   //    }
  */
 function addISBN(book: Book, ISBN: string): Book {
-  // write your code here...
+  book.ISBN = ISBN;
 
   return book;
 }
@@ -109,7 +111,7 @@ function addISBN(book: Book, ISBN: string): Book {
  *   //    }
  */
 function updatePublishedYear(book: Book, newYear: number): Book {
-  // write your code here...
+  book.publishedYear = newYear;
 
   return book;
 }
@@ -134,10 +136,18 @@ function updatePublishedYear(book: Book, newYear: number): Book {
  *   //    }
  */
 function addSecondAuthor(book: Book, additionalAuthor: string): Book {
-  // write your code here...
-
+  if (Array.isArray(book.author)) {
+    let newArray = book.author;
+    book.author.push(additionalAuthor);
+    book.author = newArray;
+  } else if (typeof book.author === "string") {
+    let newArray = [book.author];
+    newArray.push(additionalAuthor);
+    book.author = newArray;
+  }
   return book;
 }
+console.log(addSecondAuthor(book, "test"));
 
 export {
   createBook,