Widely admired for his skill as a physicist and his power to persuade legislators to fund SLAC's projects, Richter shared the Nobel Prize in physics for the discovery of the charm quark in 1976. As director he put some bends in SLAC's linear accelerator, transforming it into a more powerful machine that could collide electrons and positrons head-on.

Richter leaves the lab with a newly minted B factory, designed to ferret out why there is more matter than antimatter in the universe (Science, 7 August, p. 764). But SLAC's fortunes may be tied to those of the Next Linear Collider, a giant 30- to 50-kilometer-long accelerator still in the planning stages, which labs all over the world are competing to have in their backyards. Richter, "infinitely smart and infinitely persuasive," would have enhanced SLAC's chances in this competition, says longtime colleague George Trilling, a physicist at the University of California, Berkeley.

Who will fill Richter's size-15 shoes? Insiders suspect B factory project director Jonathan Dorfan may be the pick--unless Fermilab lures him to Illinois to replace its own outgoing director, John Peoples.