As already mentioned, David Blackwell is best known for being the first African American inducted into the National Academy of Sciences, which of course is based upon research accomplishments. Now many researchers, I suspect, secretly imagine themselves as Captain Kirk types, cruising across the research frontier and boldly pushing outwards. In contrast, David is known for quotes like "I'm not interested in research and I never have been". This sounds weird at first, like seeing an actor accepting an Oscar and saying "I'm not interested in acting and I never have been". But David goes on to say "I'm interested in understanding, which is quite a different thing. And often to understand something you have to work it out yourself". And this was a hallmark of his career.
[Balloon pops noisily] Missed again!
For instance, after thinking about the foundations of Statistics, David became a Bayesian, long before this was popular, and in 1970 published a definitive introductory textbook (Basic Statstics) based on his Berkeley course.
Another instance concerns Game Theory, which by the 1970s had become a rather narrow discipline studied in theoretical economics, but David started thinking for himself from first principles and relating it to Statistics -- this led to another influential 1979 textbook Theory of Games and Statistical Decisions.
Finally I often repeat his advice to seminar speakers: "Look, don't tell me everything. Just tell me one or two interesting things". Following this advice let me turn the podium over to the Blackwell family.