The book overall explains the things you need to know for the exam quite well and it is well written. Studying from this book and taking tests over the web I was able to achieve 83% on the programmer exam. I haven't read through any other of the certification books but feel that this book does a decent job at preparing you for the test. I have not done the developers exam so I can't comment on that section of the book.There are numerous typos and some erroronous statements, see the errata section on the publishers website, including the IO section seeminly like it is included in the programmers exam whereas it is not and the cd-rom and practice exams still containing AWT questions. You can order an update cd from the publisher but you need to send the cd that came with your book to them in exchange which leaves you without a cd for a couple weeks.