Heidi did a wonderful retrospective/obituary of Rauschenberg over at The Beat and I don't think I can add much to her words beyond a few personal observations.
I became aware and influenced by the works of Marcel Duchamp, Jasper Johns, and Robert Rauschenberg at more or less the same time.
My favorite Rauchenberg piece has to be "Erased de Kooning." It most captures the many influences that Rauchenberg was channeling as a young and ambitious artist on the verge of a major Break-Out as we say in the Beanworld--even though the art world at large was ingnoring everything he was painting.
Somewhere along the line he became intrigued with the notion of erasing as the flip side of drawing. "I had been working for some time at erasing," he told art historian, Calvin Tomkins in The Bride and the Bachelors, "I wanted to create a work of art by that method."
Raushenburg recognized that erasing one of his own drawings did not have the impact or effect that he was seeking. "I realized that it had to be something by someone everyone agreed was great, and the most logical person for that was de Kooning."
So the eager young Unknown Artist went to the studio of the Older Famous Artist and pitched him his radical idea. De Kooning didn't toss him out on his ear, instead he not only "got it" but he chose a drawing that de Kooning said he" would miss."
De Kooning chose a drawing that Raushenberg would really have to work HARD at erasing. Raushenberg explains the history of this artwork over at YouTube and the clip is well worth watching. "He gave me something that had charcoal, oil paint, pencil, crayon, I spent a month erasing that little drawing."
Rauchenberg later told Tomkins, "It wasn't easy, by any means. The drawing was done with a hard line, and it was greasy too, so I had to work very hard on it, using every sort of eraser. But in the end it really worked. I liked the result. I felt it was a legitimate work of art, created by the technique of erasing."
As I was writing the above, I went out the door of my studio and snapped the pic below. It's the bottom shelf where I keep the big books that I've referred to the most over the years, which explains how tattered some of them have gotten over the decades. Rauchenburg is right next to Duchamp!

