Whodunit? Murder by the Book, that's who. The 26-year-old Inner Loop book nook has retained a loyal following despite the proliferation of enormous chains in its immediate neighborhood. Many patrons of the indie store are die-hard mystery fans who go to see and hear the parade of prestigious and up-and-coming mystery authors who give readings there several times a week. Some go in search of the stacks of signed first editions, the abundance of rare and collector books, the award-winning bimonthly magazine The Dead Beat or to attend the monthly mystery book club. Still others have been clued in to the genuinely good service and informed recommendations of its staff and have switched to reading mysteries as a matter of principle. It doesn't take a detective to see why Houston readers have made this place their favorite for decades.