The Book of Mormon fits into none of these categories.
Musicals have undergone a shift in the last fifteen years and most new shows are rock operas (Rent), adaptations of famed movies (Shrek, Legally Blonde) or jukebox musicals which steal their material from the songbooks of famed artists (Jersey Boys, Mamma Mia). The Book of Mormon fits into none of these categories. It is an original show that marries a classic musical structure with a modern aesthetic. Created by Matt Stone and Trey Parker, the satirists behind South Park, and Robert Lopez, the co-creator of Avenue Q, The Book of Mormon is a surprisingly sweet story of two Mormon missionaries whose faith is tested when they’re sent to AIDS-ravaged Africa.
To get around this, movies like Chicago and Nine turned musical numbers into fantasy sequences while shows like Shrek, Spamalot and Urinetown perform every song with a post-modern wink to the audience. Meanwhile Once, the musical which swept the 2012 Tony Awards, professes to be a musical even though not a single song actually advances the plot. Switch any song in Once with a song by your favorite recording artist and you’ll find the story is almost exactly the same. I adore Once but the fact remains it ignores the usual convention of musicals, providing songs that are sung simply because the characters are musicians and singing songs is what musicians do.
Stuart Munro has also reviewed Book of Mormon for CharPo