1. Wikipedia: Wikipedia offers concise summaries of books in dedicated articles. While not always as detailed as other sources, it's a good starting point for a brief overview.
2. Goodreads: Goodreads is a large social networking site for readers. Many books on Goodreads have user-submitted summaries, often providing a more personal perspective.
3. BookBub: BookBub is an email service that sends daily deals and recommendations on eBooks. It also has a section dedicated to book summaries.
4. SparkNotes: SparkNotes offers detailed chapter summaries, analysis, and study guides for popular literature and textbooks.
5. CliffsNotes: CliffsNotes provides study guides, including summaries, for a wide range of literature, as well as other subjects like history and math.
6. Schmoop: Schmoop offers modern interpretations and summaries of some classic and contemporary literature.
7. LitCharts: LitCharts offers detailed analysis and study guides for various literature, including plot summaries, character analyses, and theme exploration.
8. Summaries.com: Summaries.com presents concise and spoiler-free summaries of popular books.
9. BookRags: BookRags provides detailed study guides and summaries, often with analysis, insights, and essay topics.
10. Novel Summary: Novel Summary offers short summaries of classic and contemporary literature.
11. Google Books: In the Google Books search results, clicking on the book's title will often display a brief summary.
Remember, while these websites offer valuable insights and overviews, they should not replace reading the original text for a comprehensive understanding and appreciation of the book's content.