Lost Horizon is the story of Hugh Conway, an English explorer who stumbles upon the lost city of Shangri-La. There he discovers a utopian society focused not on material gain or personal ambition but on a search for enlightenment and a pursuit of peace in all aspects of one's life. Conway becomes a devotee of Shrangri-La, albeit reluctantly, and returns years later after recounting his experiences to a friend. His ultimate fate is unknown.
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Their book summaries aren't as good as other providers, but PinkMonkey often has interesting insights that aren't mentioned elsewhere on the Internet. For example, they go over literary elements (like setting, conflict, and mood), compare and contrast, and symbolism/motifs. It's a good site if you want to find a unique fact or angle that other students don't know about.
Includes the standard sections found in most book notes, including a book synopsis, chapter by chapter analysis, author biography, character list, essay topics, book report ideas, and study questions. This website is less comprehensive than other book notes sites, but could be useful if you're looking for a quick review.