I'm not sure if this link has been posted anywhere yet. There are a multitude of books available in pdf format; click on the person you're interested in, then select a book, some are downloadable and some are not.
There's something for everyone, and it covers bodybuilding, strongman, strength...pretty much all aspects, even basic gymnastic stuff...as well as items you may just find enjoyable due to their historical value.
Since it's such a vast site and they are continually adding the new pdf formatted items, if you find one of particular interest which you feel others will benefit from, whether it be a certain page or chapter within the book, please post the exact url to the item in this thread, for ease of reference to others.
Eugen Sandow & The Golden Age of Iron Men