I'm still reading the Great Book of Amber. Apparently it consists of two series, the first (6 books) centers on Corwin, and the second (4 books) on his son. I had only read the first series before. IMO the quality drops in the second series. The faults which were already present in the first one are worse here, especially the characters which I do not find very believable. I'm still reading and enjoying it though
Edit: oops, looks like I got it wrong, both series have 5 books.