Best in-depth overview?

I’m not very well versed in philosophy, but I would like to learn. My main interests would lie in continental thought (existentialism/structuralism). It is my understanding that these areas require a solid knowledge of the Western philosophical canon, but I would like to get to that point as fast as possible. What’s a book that sums up philosophy till that point with a reasonable amount of detail, enough that I would understand guys like Sartre and Derrida?