This book was used for self-study of the Edexcel iGCSE Biology exam, gaining great results!
The book is divided into easy to follow units and sections, with practise questions at the end of each unit then at the end of each section (there are several units per section) - the answers for these can be found on the Pearson website.
Each unit covers a specific topic, which is described clearly and is easy to follow. There are plenty of diagrams and images, all of which aid understanding.
I started this book not understanding Biology and not only did this book help me understand it but more importantly, I now enjoy it too! Great book.