Richard Garwin obituary

Physicist and US government adviser who designed the first working hydrogen bomb

The Nobel laureate Enrico Fermi called his student Richard Garwin the only true genius I've ever met". Garwin, who has died aged 97, is perhaps the most influential 20th-century scientist that you have never heard of, because he produced much of his work under the constraints of national or commercial secrecy. During 40 years working at IBM on an endless stream of research projects, he was granted 47 patents, in diverse areas including magnetic resonance imaging, high-speed laser printers and touch-screen monitors. Garwin, a polymath who was adviser to six US presidents, wrote papers on space weapons, pandemics, radioactive waste disposal, catastrophic risks and nuclear disarmament.

Throughout much of that time, a greater secret remained: in 1951, aged 23, he had designed the world's first hydrogen bomb.