IV · Data & databases
Rudolf Bayer
1939–
TU München emeritus · Boeing Research
Gave us
B-trees (1971, with Edward McCreight). Red-black trees (1972, "symmetric binary B-trees"). Most of how indexes work, full stop.
The story
Designed B-trees while working at Boeing's research labs. Refused to commit to what the "B" stood for — Bayer? Balanced? Boeing? Broad?
One more thing
The B in B-tree is officially "the letter that comes after A-tree". This is the canonical answer.