Hit or miss with this collection. Starts with a weak storyline which is not consistent author to author. Some stories (including George Martin's) are excellent. The Star Wars collections of compilations are better.
I think the beginning of a book is the hardest part to read, you do not know the characters; and you don't care for they yet. This book, each author gets a chapter. Each author introduced his Hero. It was like starting 12 novels, one at a time. About the time I start to get into off to a new (related) but altogether different I'd love to "power thought" and read the 2nd one but I have only read 3/4 of the first one. I doubt i'll get to
