life:

Happy Birthday Muhammad Ali. Across five decades and through dozens of boxing bouts and portrait sessions, in this gallery photographer Neil Leifer talks about some of his favorite images of The Greatest of All Time.

“When I was young,” Leifer recalls, “I thought it was unprofessional to ask a subject for an autograph or to pose for a picture. But when I got an office next to [legendary LIFE photographer] Alfred Eisenstaedt, that all changed. I’d visit him because I loved listening to his stories, and I started to notice his personal pictures — Sophia Loren kissing him on the cheek, or a shot of him hanging out with Jack Kennedy, and I started thinking, ‘One day I’m going to be an older guy, and I want to be able to show my grandkids what I did during my career.’ So from that point on, I ended every session with a picture of me and my subject. This one, from 1966, is one of the very first. I look at it now and I think about how lucky I’ve been to have photographed Ali for all these years, and to consider him a friend. He is a very special human being. He truly is.”