What are some alternatives?
When comparing WikiSummaries and Book Summaries, you can also consider the following products
Blinkist - Key insights from 2,000+ bestselling nonfiction books
Four Minute Books - Making you smarter in 4 minutes or less.
GetAbstract.com - Book Summaries, Book Abstracts
12min APP - Free reading app for summaries of nonfiction books.
BookRags - Apart from book abstracts, Bookrags.
Instaread - Read or hear key takeaways of any book in minutes