Too many to list since when I discover an author I like, I conscientiously track down everything in print. However, when an author fails to please, I will give up. Neal Asher, for example, who's earlier novels I read with much enjoyment but have ignored his later output (the last 4 novels) as being painfully weak, derivative and essentially, a wearisome rehash of previous work...but lazy and unimaginative regurgitations. Sherri Tepper is another. By and large though, I am always enthralled to hear of a previously unknown writer...and if they have an immense back catalogue, then joy indeed.