Oh wow. *commence frantic downloading* Well, almost all of them are way beyond my current skill level, but I found several books that piqued my interest among the Logic & Computation subcategories. I'm sure it'll be a big help for next year. I'm hoping to study for an undergraduate degree in Logic & Computation (depending on the status of my health by that time). I did notice that several books are listed more than once. The most egregious example being "Handbook of Philosophical Logic" being listed about a dozen times.
Most of these are pdf and epub files. Not sure about hard copies. Anyway, there are other categories available for download besides philosophy.
There don't seem to be 2500 books available any longer. Today it generates 78 results, most of them distinctly underwhelming titles. So I'm guessing that making their entire library of publications available for free download might have been accidental, a serious screw-up in their online database system that they have since tried to correct.