Between 1946 and 1951, Fitzgerald harmonized on eight pop singles with Louis Armstrong, one of her central "inspirators" (to use Satchmo's own expression). However, the two albums of duets that these two jazz icons recorded in 1956-'57, Ella and Louis and Ella and Louis Again, were something else entirely. Essentially, these two savants simply improvised together in front of an equally Olympian rhythm section (Oscar Peterson, Ray Brown, Buddy Rich); in the process, they connected beautifully to everything: to the songs, to the band, and to each other. These three albums (the third of which was a stunning reading of the score to Porgy and Bess in 1958 — yet another Gershwin-Fitzgerald production) set a new standard for jazz vocal duets in the modern era.