This book is for new or aspiring computer science teachers wishing to improve their subject knowledge and gain confidence in the classroom. And it's for experienced computer science teachers who wish to hone their practice, in particular in the areas of explicit instruction, tackling misconceptions and exploring pedagogical content knowledge. You will read some of the backstory to our subject - the hinterland - those fascinating journeys into history that make the subject come alive and place it in historical context. These stories will help you to enrich your lessons, cement core knowledge, develop cultural capital and help you excite a life-long love for the subject. We will go beyond the mark scheme to explore the subject knowledge behind the answers, giving you the confidence to discuss the field in greater depth, enabling you to use explicit instruction methods: presenting skills and concepts clearly and directly enabling student mastery. We will explore misconceptions that arise when teaching our subject, so you can head them off at the pass. And we will look at teaching ideas - the pedagogical content knowledge (PCK) - exploring the helpful analogies, questions and activities that work for each topic: practices that can be lifted and dropped straight into the classroom to immediately enhance your teaching. Trainee or pre-service teachers, NQTs and early-career teachers will find this book invaluable, experienced teachers will find it inspiring, and all will benefit from a fresh look at the hinterland and subject pedagogy that makes computer science a fascinating subject to teach.