There is related information in all of the books we study, but there are three core books that outline the basics. I linked to them below.

Be aware that although the process of working on the ego has basic factors such as observation, meditation, and elimination, the precise process is different for each person, because our ego and our karma is unique to us alone, and the only way to eliminate our psychological defects is through knowing the very details of each defect, and how it manipulates us. Therefore, to explain how to observe, comprehend and eliminate our own ego would require volumes and volumes of books, which, incidentally, would only apply to oneself.