Or you can just go to Project Gutenberg which "offers over 42,000 free ebooks: choose among free epub books, free kindle books, download them or read them online." http://www.gutenberg.org/
I am not sure Elsevier's collection intersects very much with Gutenberg.
Elsevier is selling books that are copy-righted and also recent. They're more about textbooks that are used in schools.