E-Book Central is an excellent collection of (mostly) scholarly or academic books. You may download books (limited time), download chapters, print chapters, and more. Just keep following the links. You'll need to download free Adobe software.
E-book Collection is a smaller e-book database, but it may be worth searching.
Gale E-Books is a collection of e-encyclopedias; it's great for background information for subjects like history, American decades, biographies, and more. It should not be used in general when searching for scholarly, academic, or peer-reviewed works. (there is some scholarly writing in some of the encyclopedias such as Black Literature Criticism: Classic and Emerging Authors since 1950.) Type in the name of the novel, short story, poem, play, or author you are researching. Then, at the bottom, limit the results to the Collection LITERATURE. Title such as Literature and Its Times: Profiles of 300 Notable Literary Works and the Historical Events that Influenced Them, Drama for Students, African American Writers, World Poets, Contemporary Authors, Supernatural Fiction Writers: Contemporary Fantasy and Horror .
Credo Reference Academic Core is another e-encyclopedia database.