The A+ Certification book contains a number of errors, is only about 50% complete with CompTIA requirements, and questions on the exam simulator are much much easier than on the real test.
They follow the headings of CompTIA's requirements, but do not provide sufficient information. For example, one test question compared fast paged RAM with another type of RAM. This book only mentions that fast paged RAM exists, but does not include more detail because it is not common enough.
Check the disclaimer if you want to find out how good this book is. It says "McGraw Hill does not guarantee the accuracy, adequacy, or completeness of any information and is not responsible for errors or omissions or the results obtained from use of such information." Of course, this is printed inside the book so you can't see it until you've lost your money.
What is this, a text book or a bloody NOVEL!!!!!