The eight-volume second edition of The Grove Dictionary of American Music is an extraordinary achievement, embodying the contributions of nearly 1500 scholars, many of whom regularly read and publish in the present journal. It was therefore with some trepidation, and a great deal of humility, that I accepted John Koegel's invitation to review the encyclopedia's coverage of twentieth- and twenty-first-century “art music.” The more I delved into this gargantuan task, the more impressed I became with the encyclopedia's scope, the high quality of writing, and the sensitivity to difficult conceptual issues in the field. (And as a side benefit, I learned about a host of people I'd not previously known.)