Cordwainer "cobbler" have often been considered not interchangeable, according to a tradition in Britain that restricted cobblers to repairing shoes. In this usage, a "cordwainer" is someone who makes new shoes using new leather, where as a "cobbler" is someone who repairs shoes. Medieval cordovan leather was used for the highest quality shoes, but cordwainers also used domestically produced leathers and were not solely producers of luxury footwear. In the historic London guild system, the cobblers and cordwainers were separate guilds, and the cobblers were forbidden from working in new leather. Historically, cobblers also made shoes, but only using old leather
Cordwainer Smith Hour." According to Cordwainer Smith scholar Alan C. Elms, this speculation first reached print in Brian Aldiss's 1973 history of science fiction, "Billion Year Spree"; Aldiss, in turn, claimed to have gotten the information from Leon Stover. More recently, both Elms and librarian Lee Weinstein have gathered circumstantial evidence to support the case for Linebarger's being Allen, but both concede there is no direct proof that Linebarger was ever a patient of Lindner's or that he suffered from a disorder similar to that of Kirk Allen. According to Frederik Pohl Linebarger's identity as "Cordwainer Smith" was secret until his death.