Written for students taking either the University of Cambridge Advanced Level examinations or the International Baccalaureate examinations, this guidebook covers essential topics and concepts under both stipulated chemistry syllabi. The book is written in such a way as to guide the reader through the understanding and applications of essential chemical concepts using the problem-solving approach. The authors have also retained the popular discourse feature from their previous two books -- Understanding Advanced Physical Inorganic Chemistry and Understanding Advanced Organic and Analytical Chemistry -- to help the learners better understand and see for themselves, how the concepts should be applied during solving problems. Based on the Socratic Method, questions are implanted throughout the book to help facilitate the reader's development in forming logical conclusions of the concepts and the way they are being applied to explain the problems. In addition, the authors have also included important summaries and concept maps to help the learners to recall, remember, reinforce, and apply the fundamental chemical concepts in a simple way.