This book aims to provide students with a comprehensive revision course that will help them prepare for their GCE O Level examinations. Each chapter of the book consists of: 1. Overview of The Topic: Overview gives students a full picture of the topic. It shows the students the structure and all the key areas of the chapter. 2. Objectives: Objectives based on the latest syllabus are given in this part. Students should make sure that they are able to meet all the expectations before taking the examination. 3. Key Points: This part is featured by concise study notes. All main points and formulae are presented to help students consolidate their knowledge learnt in class. 4. Exam Tips: Common mistakes, misconceptions and important reminders are listed in this part. 5. Stop & Think (Challenging questions with solutions): For each chapter, different types of questions appearing in the examination are included to enhance students examination techniques. All these questions are provided with answers and explanations. Challenging exam-type questions are provided at the end of every chapter. The exercises enable students to have constant practice in order for them to apply the concepts that they have learnt. Fully worked out solutions are provided to show pupils the correct way to present their workings and derive the answers.