Although the venue Off Broadway has long been the birthplace of innovative and popular musicals, there have been few studies of these influential works. Long-running champs, such as The Fantasticks and Little Shop of Horrors, are discussed in many books about American musicals, but what of the hundreds of other Off-Broadway musicals? In Off-Broadway Musicals since 1919, Thomas Hischak looks at more than 375 musicals, which are described, discussed,...