For my preparation of the CIA exams, I exclusively used Gleim CIA Review hand books and CIA Test Bank. They allowed me to quickly take and pass all exams needed for the certification. I always started by one or two readings of the books. I very much appreciated the concise but clear and complete explanations provided. Next, I would switch to the online multiple-choice questions. They are great for discovering your knowledge gaps. Furthermore, Gleim provides explanations of all the correct answers that are very insightful. I always ended with reviewing my errors by reading the explanations. As a bonus, the style of the online questions also resembles the style of the questions you will see on the exam, which is perfect to get acquainted with the exam format.
Thanks to the study material of Gleim, I managed to complete all parts in only a couple of months and was awarded with a Certificate of Excellence. In short, I highly recommend Gleim for anyone preparing for the CIA exams or willing to improve his or her internal audit expertise. I still apply the concepts used in my day-to-day audit activities.