This book is based on the contents of the WJEC Units 3 & 4 A Level specification.  The book is aimed at those students wishing to gain a more in depth coverage of the theory and focusses on the understanding of topics from the ground up.  There are no exam style questions as the author does not wish to teach to the exams, rather, the author wants to focus on understanding so that the student can think for themselves and be able to answer a wide range of questions and not necessarily those from just one exam board.  Throughout the book, there are many illustrations to help the student visualise difficult concepts along with many sample problems with solutions to consolidate learning.

Optional units are NOT included.