Like Wuthering Heights, the scenery and setting in this brooding book are extremely important, creating and refelcting mood. Here, rather than the Yorkshire Moors, it's Bodmin Moor in Cornwall. Within these bleak and hostile moors sits the solitary and isolated inn of the title (still there in real life), presided over by the frightening and cruel drunkard, Joss Merlyn. But is he the real villain, or is he just being used by an even more powerful force?
What I particulalty like about this book is that it's set in Victorian times, reads very much like a Victiorian novel, but is not blunted by that era's strict censorship (Jamaica Inn was published in the - slightly- freer 1930s). Mary and Jem actually do frolic quite suggestively, despite not being married, and this behaviour is not damned by the narrative.
It is interesting that Hitchcock made films of three Du Maurier works. As well as Jamaica Inn, The Birds and Rebecca are also based on her stories. He must have been a fan.