Bruce Mueller is the rock expert who brought you the very popular ""Complete Guide to Petoskey Stones"". Bookstores all along Lake Michigan loved that book, but they also expressed many requests for a rock identification guide for Lake Michigan. Here it is. Mueller researched the entire shoreline of Lake Michigan to write this guide to Lake Michigan rocks. This is the perfect guidebook for any-one or any family who walks the beach and wonders, ""What is this?