In 1971, “next to nothing was known about the organization of membrane proteins,” says S. Jonathan Singer (University of California, San Diego, CA). Singer had proposed that there were two kinds of membrane proteins— integral and peripheral—but the idea was, at the time, largely speculative (Singer, 1971). It was a collaborative study between Singer, his then graduate student Garth Nicolson, and Vincent Marchesi of the National Institutes of Health that provided strong evidence for the existence of peripheral proteins (Nicolson et al., 1971a).