After a successful singing career in the 1950s, Tony Bennett, like many of the jazz-based crooners of his era, had a bit of a commercial falloff with the advent of rock & roll in the early '60s.

Bennett, for his part, moved even closer to jazz in his stage shows, and then saw his popularity spike when his signature song, "I Left My Heart in San Francisco," became a big pop hit in 1962.

It was Bennett at his best, working to the pop side of jazz, and as the '60s progressed, Bennett became firmly established as an iconic singer and entertainer, his singing always warm, graceful, and full of an easy and offhand elegance.

He picked his material carefully, avoiding novelty and trendy songs, and he built an impressive catalog of classic songs, many of which are firmly established as part of the ever shifting American Songbook.

This two-disc set is interesting because the selections were made by Bennett himself, with the first disc, easily the best of the two, given over to Bennett as a solo singer, while the second is drawn largely from his two Duets albums and features Bennett performing with Frank Sinatra, Ray Charles, Stevie Wonder, Christina Aguilera, Lady Gaga, and others.

But it's the solo performances that really capture him at his best.

Bennett has noted that he started with the song itself in making the selections here, and then looked for what he thought was the best performance and presentation of it, and since he's released nearly 70 albums in his long career, and many of those were live shows, he had a lot of performances to choose from.

There are wonderful versions here of "I Left My Heart in San Francisco," "I Wanna Be Around," and his other signature songs, all of which come off as emotionally warm and compelling, with an easy and lightly swinging jazz feel.

The duets disc has the same warm vibe, and Bennett is a gracious and generous duet vocalist, but to hear him take a great song and broaden it and build it vocally into a perfectly balanced emotional piece of art, well, he doesn't need to share the stage with anybody to do that.