Are you a girl or young woman aged 13-18? If so, this book is for you! Amanda Stent and Philip Lewis have written a gentle, friendly and comprehensive introduction to computer science. Each chapter covers one area of computer science and includes: examples of how the computer science works; sidebars that contain historical notes or ideas for you to explore; and biographies of women in computer science. The last chapter covers questions that you might have about becoming a computer scientist. We hope that after reading this book you will want to join us in studying this uniquely beautiful and practical subject.