by Scott Yanow 　　  　　This four-LP box set, whose contents have been partly reissued on CD, has all of singer Helen Merrill's output for Mercury; only two selections for the Roost label in 1953 precede these definitive recordings. Merrill, whose warm voice was always both distinctive and flexible, could hold her own with the best jazz musicians of the era. Best known of her recordings are her classic collaborations with Clifford Brown on seven selections arranged by Quincy Jones (including "You'd Be So Nice to Come Home To" and "Falling in Love With Love"), but almost as significant was a notable album on which she employed the little-known Gil Evans as arranger, a year before he teamed up with Miles Davis for Miles Ahead. Other Mercury dates include work with the Johnny Richards Orchestra, arranger Hal Mooney, flutist Bobby Jaspar, and pianist Bill Evans. Highlights include "Glad to Be Unhappy," "Spring Will Be a Little Late This Year," "Anyplace I Hang My Hat Is Home," "Where Flamingos Fly," and "The Things We Did Last Summer," but all 62 selections are well worth hearing. Highly recommended.