Jeff Garzik is a bitcoin developer, Linux kernel engineer, and cloud computing hacker.
He is the co-Founder of Bloq Inc, a company that provides enterprise grade blockchain technology to leading companies worldwide.
Garzik was a contributor to the Bitcoin Core project in the past.
He was also the author of a multi-threaded CPU miner for bitcoin called cpuminer. Many past and current bitcoin and altcoin miners (ie sgminer) are ultimately based on Garzik's cpuminer.
Garzik is now the lead developer in the Segwit2x project, which aims to upgrade Bitcoin Core by raising the block size limit to 2MB.