Hogan's book has been continuously in print for over fifty years. Most other golf swing books, in contrast, disappear from print within a year or so. Hogan's book is exceptionally clear and detailed about all the swing fundamentals. Consequently it enables one to figure out, when needs must, what's going wrong with one's swing and how to correct it.
Hogan's book is also unique in demonstrating how each swing fundamental links with the others. Other golf swing books, in contrast, tend towards being just compilations of swing tips. So, where other books provide swing band-aids, Hogan's illuminates and helps develop real understanding.
Hogan's book has been called, rightly in my opinion, 'the bible of the golf swing'. All modern golf swing theorists, as is clear from their writings, merely repackage or add footnotes to Hogan.
Go to the source, to the benefit of both swing and understanding, read Hogan's timeless classic.