If you're going to read The Crucible of Creation
by Simon Conway Morris then you'll need to know about Wonderful Life
in which Stephen J Gould argues for contingency in evolution, based upon the reinterpretation of the Burgess Shale fauna - in which Conway Morris played a significant part. But Conway Morris clearly doesn't like his work being used in support of an idea which he disagrees with, and so argues against it in this book. Unfortunately this leads to the book having a very strange first chapter, which seems more like a rant than reasoned argument - the author seems prone to repeat simple arguments which have already been addressed in Gould's book.
After the first chapter the book settles down into a more normal flow, describing the discovery of the Edicarian fossils and the Burgess Shale, and going on to talk about the work done at Cambridge on these fossils. Later in the book - which is where such discussion belongs - Conway Morris looks at some of the implications, discussing at contingency and convergent evolution. Overall I feel that he gives a substantial account of the study of early fossils, and what it implies, without becoming too technical. If you don't take the first chapter too seriously then I think that you'll find much of value in this book.