Several suggestions:

Walter Havighurst, Three Flags at the Straits, the Forts of Mackinac. Excellent, very readable history.

Walter Havighurst, The Long Ships Passing, the Story of the Great Lakes. Likewise. Havighurst also wrote the book of the Upper Mississippi in the "Rivers of America Series," plus several fine histories of the midwest (Wilderness for Sale, etc.)

Two nicely illustrated books of what is often called the "coffee table" type, but containing good, concise historical essays: Land of the Inland Seas by William Donohue Ellis, and A Pictorial History of the Great Lakes by Harlan Hatcher and Erich A. Walter.

I read another quite good and well-illustrated history of the Great Lakes recently, but I'm not sure of the title and author (a woman) and I'm darned if I can put my hands on the book right now. I've got to get some new bookshelves up here and get the recent arrivals at least roughly organized!

Sandy (who would like to be a bookstore when he grows up!)