SO,
There are almost 30,000 volumes on http://www.gutenberg.org.
Free download, some in .txt and some in HTML. The HTML versions have illustrations and are a pleasure to read.
Some of the books have been out-of-print so long you simply cannot find a copy.
If you like classic literature this is a good site.
But, just like digital signal processors in music allowing musicians to access hundreds of samples of guitar amps, for example, there is no replacing the harmonics of an old tube amp.
I'll take an old Fender Twin Reverb amp over a digital signal processor any day.