A good fashion designers book is one of those things that every fashion enthusiast must own. Not only can a good book introduce you to the best of the latest style collections in the most appropriate and systematic way, but it can also help unleash the creativity in you. A good book does not only teach, but it also helps you realize what your aspirations are and what you can do to make your own style statement.
While selecting a fashion book, it is a good idea to make sure that it contains the kind of stuff that matches your needs and tastes. For instance, if you are mostly into casual wears, then there is no point in buying something that deals with formal suits and ties. A good idea in such cases is to instead check the famous magazines and see how much you like them. If the magazines are too expensive you can keep a watch out for garage sales, etc, where you can get second hand magazines at really cheap prices.
For the more serious learner, however, it is a great idea to opt for something that is less commercial and teaches style more directly and seriously. Find out about the books that designers in fashion prescribe for their students, since they make great options.
Also, once you have purchased a fashion designers book, take adequate care to keep it well. Do not do away with those books just because you are tired of seeing the same things again and again.
Collect them and store them away if needed, because there is quite a good chance that someday in future you would want to dig them out again and refresh your memory with the same things you got tired of earlier!