Jerome Kern's Jewel Box shows how the integration of spoken and sung performances in Kern's early musicals reveals new connections between musical theater scores and "straight" (spoken) theater. Kern's scores are foundational to the American musical, and subsequent dramatic music would be unrecognizable without Kern's innovations. This book argues that Kern's scores for a group of musicals staged at the Princess Theatre embody a musical corollary to the Realist drama of the Little Theatre Movement. The umbrella term "Princess musicals" includes the four musicals that Jerome Kern composed for New York City's Princess Theatre: Nobody Home (1915), Very Good Eddie (also 1915), Oh, Boy! (1917), and Oh, Lady! Lady!! (1918), as well as Leave It to Jane (1917), a musical conceived for the Princess. Each separate Princess musical bears distinct hallmarks of Little Theatre sensibility, and that these hallmarks are overwhelmingly represented in the sung/musical portions of the drama. The book's first chapter explores the influences of WWI and the Little Theatre Movement on the American stage (legitimate and musical). The subsequent chapters are studies of the five so-called "intimate musical comedies" that resulted from Kern's engagement with these influences. The case studies all demonstrate how the shows' scores advance the same artistic aims voiced by prominent members of the Little Theatre Movement. Ultimately, this project leads musical theater historians to reconsider the place of musicals in relation to the legitimate theatre and the historiography we  construct around the "integrated" musical.