Mr. McDowell said he saved the magazines because they are “the quickest and most memorable source of information,” and that he is “more interested in how clothes are featured in magazines than in their catwalk life,” as well as in fashion photography and illustration trends. Mr. Hyman accepted the magazines on the condition that Mr. McDowell can recover them from the archive should he need them and that his collection remain intact.

Jeremy Leslie, the owner of MagCulture, a magazine shop in London that serves as the locus of a boom in independent magazine publishing in England, said that because magazines by their very nature are rushed to press, they reflect the particular quirks of society during short intervals of time.

“In order to understand the value of the Hyman Archive, you have to understand the value of magazines above and beyond their contemporary purpose,” he said. “There is a canon of great magazines that is forming, but actually when you look through even magazines that are central to that canon, you see the pages you don’t get shown. There are so many subplots to this bigger picture that don’t get spotted unless you have the whole thing.”

This is especially true of niche magazines or ones that aren’t widely thought of as classics, Mr. Leslie said. “When you come to look at something from 10 or 20 or 30 years ago, there are obvious kinds of historical archive-worthy elements, but they are also a great record of design trends, typefaces, photography, writing and technology, so they are fantastic records of time gone.”

During a recent visit, Mr. Hyman showed a reporter some of the titles and design elements he considers particularly important, including fake ads from Mad magazine trolling the cigarette industry; Kate Moss’s first cover (The Face, July 1990); The Notorious B.I.G.’s first appearance in The Source (March 1992); Rihanna on the cover of the first free issue of New Musical Express (September 2015) and a hacking magazine from 1984 called 2600, which, Mr. Hyman said, “is the frequency you used to use to get free calls if you blow your Cap’n Crunch whistle down the phone line,” and lists all of the direct phone extensions in the Reagan White House.