I purchased this book, and my problems were solved exactly. You won't need to go to courses, trainings, etc. Only this book is sufficient for you. I also recommend Test King's questions, the questions are very similar to the real CCNA exam. To be successfull on simulation questions, I recommend you to study with Boson Router Simulator. You can establish your own topology and study whatever you want.Good luck on CCNA exam...Burak Sezer