"The Last Sweet Days of Isaac" is my favorite rock musical thus far for three reasons: (a) The songs end when they are over; (b) While a boy and girl are doing all that talking about coming alive, they are alive; and (c) Language at last is beginning to rise to the beat.

Take the last first. For the first time in my experience, someone—Gretchen Cryer, it turns out—has succeeded in writing a book that is not only as good as the music but walks right into the music without hemming and hawing about it. I say "book," although [it] is really (let's be honest) two enchanting one-acters….

But the writing is actual writing—not pretentious writing, mind you, not self-conscious in its casual poetry, but not baby babble or mere latrine leftovers, either. (p. 1)

The evening is small (but that may be one reason why...