Which one of the H.P Lovecraft book should i read?

I have been looking around and i think i like him but a haven't reed any of his work. So i wonder which one of the book should i read? I like the Cthuhlu thing and want a book that covers "the basics" of that. And also what's the rest of the Cthuhlu books about? And is the movie (from 2007) good?