I recently bought two books about Washington Island. They are "Let's Talk about Washington Island 1850-1950" by Anne T. Whitney which is sometimes called the Washington Island Centennial Book.
The second book is "Washington Island 1836-1876" by local author Conan Bryant Eaton. Both of these books would be valuable resources for genealogists with family in this area.
Please contact me if you have an interest in these books.Kathy@FamilyWeSearch.com