After 27 years, Jeff Dean is leaving Google: His ‘goodbye email’ explains why

Jeff Dean is leaving Google after 27 years, closing a run that took him from employee number 30 to chief scientist. He built MapReduce and BigTable, started the TPU program, founded Google Brain and co-led Gemini. Now he's CEO of Discovery Loop, chasing AI that improves itself. His farewell note lists it all, plus 18 office moves and Monterey bike rides.