diff --git a/modules/4_oop/index.js b/modules/4_oop/index.js
index a06168f..f9142e9 100644
--- a/modules/4_oop/index.js
+++ b/modules/4_oop/index.js
@@ -4,22 +4,115 @@
  * @param {number} x
  * @param {number} y
  */
-export class Point {}
+export class Point {
+    constructor(x, y){
+        if(!x || !y) {
+            throw 'x or y is not provided'
+        }
+        this.x = x
+        this.y = y
+    }
+
+    plus(point){
+        return new Point(this.x + point.x, this.y + point.y)
+    }
+}
 
 /**
  * Speaker and Screamer ES5
  */
-export function SpeakerES5() {}
-export function ScreamerES5() {}
+export function SpeakerES5(name) {
+    if(!name) throw "name is empty"
+    this.name = name
+    this.speak = function speak(sound) {
+        console.log(sound)
+    }
+}
+export function ScreamerES5(name) {
+    SpeakerES5.call(this, name)
+    this.speak = function speak(sound) {
+        console.log(sound.toUpperCase())
+    }
+}
 
 /**
  * Speaker and Screamer ES6
  */
-export class SpeakerES6 {}
-export class ScreamerES6 {}
+export class SpeakerES6 {
+    constructor(name){ 
+        if(!name) throw "name is empty"
+        this.name = name
+    }
+    speak(sound){
+        console.log(sound)
+    }
+}
+export class ScreamerES6 {
+    constructor(name) {
+        super(name)
+    }
+    speak(sound) {
+        console.log(sound.toUpperCase())
+    }
+}
 
 /**
  * The Reading list
  */
-export class BookList {}
-export class Book {}
+export class BookList {
+    constructor(){
+        this.booksFinished = 0
+        this.nextBook = null
+        this.currentBook = null
+        this.lastBook = null
+        this.books = []
+        this.notReadBooks = []
+    }
+
+    add(book){
+        if (!book || !Book.prototype.isPrototypeOf(book)) {
+            throw 'please provide a valid book'
+        }
+        this.books.push(book)
+        this.notReadBooks.push(book)
+        if(this.notReadBooks.length === 1) this.currentBook = book
+    }
+    finishCurrentBook(){
+       this.currentBook.markAsRead()
+       this.lastBook = this.currentBook
+       
+       var index = this.notReadBooks.indexOf(this.currentBook);
+       if (index > -1) {
+           this.notReadBooks.splice(index, 1);
+       }
+       if (this.notReadBooks.length > 0){
+           this.currentBook = this.notReadBooks[0]
+       } else {
+           this.currentBook = null
+       }
+
+       if(this.notReadBooks.length > 1){
+           this.nextBook = this.notReadBooks[1]
+       }else{
+           this.nextBook = null
+       }
+    }
+}
+export class Book {
+    constructor(book){
+        if(!book || !book.title){
+            throw 'book title is required'
+        }
+
+        this.title = book.title
+        this.genre = !book.genre ? null : book.genre
+        this.isRead = !book.isRead ? false : book.isRead
+        this.dateFinished = !book.dateFinished ? null : book.dateFinished 
+
+    }
+
+    markAsRead(){
+        this.isRead = true
+        this.dateFinished = Date.now()
+    } 
+}