Devil in a Blue Dress is the story of Easy Rawlins, a black day laborer who becomes a hard-boiled private eye. Rawlins becomes tangled up in the web of femme fatale Daphne Monet, a damsel in distress who is in actuality a black woman named Ruby passing for white and working as a thief. The novel deals with gender relations, blackness, racism, and the deconstruction of the archetype of the private eye.
Boasting the largest collection of book summaries, BookRags is the best option for titles you can't find elsewhere. They offer all of the basics (quotes, chapter summary, characters, historical context, literary criticism) but also walk through a few major topics that recur throughout the book, which can be particularly useful for essay writing.
You won't get any frills with GradeSaver -- just the content you expect. Their study guides include a full plot summary, themes and character analysis, study questions, and the e-text of the book. One hidden gem is their collection of literature essays, but you'll have to pay for it.