The Guest Book by Sarah Blake is a page-turning summer potboiler. Set in Maine, it follows a powerful “tribe” of WASPs, aka the Milton family, through three generations marked by too many bad decisions. The fallout never seems to end. The island bought in the 1930s that is the family refuge functions as a character as well. This is a multi-generation family saga with some tragic elements. The prose is smooth so the book flows well.