diff --git a/src/exercises/ex_q3/Book.java b/src/exercises/ex_q3/Book.java
new file mode 100644
index 0000000..39d6118
--- /dev/null
+++ b/src/exercises/ex_q3/Book.java
@@ -0,0 +1,8 @@
+package exercises.ex_q3;
+
+public record Book(String ISBN, String title, String authorFirstName, String authorLastName, int year) implements Comparable<Book> {
+    @Override
+    public int compareTo(Book o) {
+        return title.compareTo(o.title);
+    }
+}
diff --git a/src/exercises/ex_q3/BookGenerator.java b/src/exercises/ex_q3/BookGenerator.java
new file mode 100644
index 0000000..bc89237
--- /dev/null
+++ b/src/exercises/ex_q3/BookGenerator.java
@@ -0,0 +1,67 @@
+package exercises.ex_q3;
+
+import java.util.ArrayList;
+import java.util.Random;
+
+public class BookGenerator {
+    private static final String[] adjectives = {
+        "big", "red", "small", "weird", "amazing", "fantastic", "friendly", "curious", "frightening",
+    };
+    private static final String[] nouns = {
+        "apple", "car", "gingerbread man", "octopus", "planet", "volcano", "bottle", "adventure"
+    };
+    private static final String[] determinants = {"the", "a"};
+    private static final String vowels = "aeiou";
+
+    private static final String[] firstnames = {
+        "John", "Patrick", "Gérard", "Jean-Michel", "Ronswalle", "Guilherme", "Jean-Claude", "Perceval", "Hector", "Ferguson",
+        "Azénor", "Clémentine", "Ailizabette", "Bérangère", "Clothilde", "Mélissandre"
+    };
+
+    private static final String[] lastnames = {
+        "de Mont-Castel", "Smith", "Martin", "Ferguson", "Lassalle", "Berset", "Constantin"
+    };
+
+    private static final Random random = new Random();
+
+    private static String getRandom(String[] list) {
+        int i = random.nextInt(list.length);
+        return list[i];
+    }
+
+    public static Book generateRandomBook() {
+        String noun = getRandom(nouns);
+        String adj = getRandom(adjectives);
+        String det = getRandom(determinants);
+        if (det.equals("a") && vowels.contains(adj.substring(0, 1))) {
+            det += "n";
+        }
+        String title = det + " " + adj + " " + noun;
+        title = title.substring(0, 1).toUpperCase() + title.substring(1);
+
+        String isbn = "";
+        int checksum = 0;
+        for (int i = 0; i < 9; i++) {
+            int digit = random.nextInt(10);
+            isbn += String.valueOf(digit);
+            if (i % 4 == 0) {
+                isbn += "-";
+            }
+            checksum += (10 - i) * digit;
+        }
+        checksum = checksum % 11;
+        if (checksum != 0) {
+            checksum = 11 - checksum;
+        }
+        if (checksum == 10) {
+            isbn += "X";
+        } else {
+            isbn += String.valueOf(checksum);
+        }
+
+        String firstname = getRandom(firstnames);
+        String lastname = getRandom(lastnames);
+
+        return new Book(isbn, title, firstname, lastname, random.nextInt(1000, 2025));
+    }
+}
diff --git a/src/exercises/ex_q3/Library.java b/src/exercises/ex_q3/Library.java
new file mode 100644
index 0000000..ab6d177
--- /dev/null
+++ b/src/exercises/ex_q3/Library.java
@@ -0,0 +1,20 @@
+package exercises.ex_q3;
+
+import java.util.Arrays;
+
+public class Library {
+    private static final int SIZE = 100_000;
+    private static final Book[] books = new Book[SIZE];
+
+    public static void main(String[] args) {
+        for (int i = 0; i < SIZE; i++) {
+            Book book = BookGenerator.generateRandomBook();
+            books[i] = book;
+        }
+
+        Arrays.parallelSort(books);
+        for (int i = 0; i < Math.min(15, SIZE); i++) {
+            System.out.println(books[i]);
+        }
+    }
+}