Cue: Lalo Schifrin's “Theme from Mission: Impossible.” If the return of Tom Cruise, explosions, and fast-paced chases to the screen this summer is any indication, Americans (and the global audience for Hollywood action film) love an impossible mission. Certainly, U.S. music scholars do. Reading the eight reviews of the second edition of The Grove Dictionary of American Music (hereafter, AmeriGrove II), edited by Charles Garrett (with a large and distinguished editorial team and nearly fifteen hundred contributors), as well as dipping frequently into its entries, we were deeply impressed both by the quality and ambition of the eight-volume, 5.4 million-word encyclopedia and by the “gargantuan” task (as Leta Miller puts it) with which the reviewers had been charged.