Lehman Engel, the man who "knows more about the American musical theatre than anyone else" (Brooks Atkinson), composer of scores of smash successes, and winner of three Tonys, raises the curtain on what makes a musical hit: MUSIC LYRICS LIBRETTOS AUDITIONS It's all here for the aspiring student, seasoned professional, and everyone else who has ever thrilled to the color, drama, and sheer excitement of the musical theatre.
I feel somewhat awkward rating this because I am completely not the intended audience. I picked this up hoping for a theoretical overview of musical theater; what I got was a practical workbook, full of exercises and long lists of songs for further study. If you actually want to write for theater, these may be useful exercises and important lists (though at this point the lists are sort of a time capsule, and what Engel considered the height of musical theater circa the 1970s is often forgotten today). If you're just curious how the musical theater industry works . . . there are still some gems here, particularly in the Libretto chapter and the essays section, but a lot of it is too technical for me and my lack of musical training to follow. That doesn't make it a bad book, just a tightly targeted one.
Engel was an influential figure in musical writing and definitely had strongly held opinions about what makes for great musical theater. On the one hand, he sounds dogmatic and preaches formulaic approaches in this guide. On the other hand, those formulaic approaches still dominate musical theater today, audiences like the formula, and veering from that formula can get you in a whole lot of trouble.
If you want to write a musical, read this book. It's comprehensive and understandable. Really breaks down the elements well and gives you lots of examples to look at.