The 48 laws of power is an excellent read. It contradicts itself at times, , but it is invaluable nonetheless.
Anyone who claims that they have learned nothing from it, has poor comprehension skills. The laws are explicitly stated, well explained, and reinforced by historical accounts of what happens when these laws are observed or ignored. As a student of management and martial arts, many of these principles have foundations in classical military and political science, referencing texts and historical figures that have been studied for hundreds and even thousands of years.