At the top of the American songwriter pantheon, one finds George Gershwin and Cole Porter and Irving Berlin. But for someone whose songs meant so much to the world of the swinging　sophisticate (just take a gander at any of Fred Astaire's classic films with songs by Berlin), his songs were surprisingly simple ?but no less charming. The comparison of Berlin's songs to Astaire's　dancing is made often, but the best of their material ?"Cheek to Cheek," "Let's Face the Music and Dance," "Top Hat, White Tie, and Tails," "Change Partners" ?was beautifully simplistic and approachable but revealed hidden subtleties and depths of technical mastery. Ella Fitzgerald, no stranger to technical mastery herself, made Berlin the subject of an early song book, circa 1958, and found such riches that it became a two-LP set. The Very Best of the Irving Berlin Song Book presents less than half of that set, but does a good job of selecting the best material. Ella, along with arranger Paul Weston and Verve head Norman Granz, chose many songs that had not been popular, and would be revelations only to vocal fans. Best of the songs here are "Change Partners" and "Blue Skies," the latter with a surprisescat opening by Ella, one of her best on record.