ML102 .M88 Musical theatre dictionaries and encyclopedias
ML410 .S95 Books about Gilbert and Sullivan
ML1700 Musical theatre and opera books
ML1711 American musical theatre and opera
ML1711.8 N3 Broadway musical theatre and NY Metropolitan Opera
ML2054 Musical theatre special topics
MT956 Practical/pedagogical books on musical theatre and opera
Here are some Subject Headings you can use to search books about musicals. Click on any of these, or go to the Libraries' Catalog. In Advanced Search, type one of these subject headings. Then chose "as a phrase" and Subject Heading from the dropdown menus at the right, To limit your search to books about musicals, choose "Book" from the dropdown menu next to the word "Type" toward the bottom of the page.