What not to wear
"Outside in the blinding sunlight, antiquated trams spew out agile targets for the Mercedes taxis. Dark-skinned young men with long black hair parade along the water's edge in bikinis almost big enough to conceal a comb." -- Harry Lime hits Beirut, early in Len Deighton's The Ipcress File.
I've asked the OED, and 'bikini' meant the same in 1962 as it does now -- and as it had done then for more than a decade. So that's either how you get homosexuality into a pre-legalisation thriller, assuming you're a mite homophobic, or a Deighton blind spot. Or both.
[The Ipcress File, by Len Deighton, Hodder & Stoughton, 1962. Has dated interestingly, if not exactly well. Much more expository dialogue than I'd like to think he could now get away with.]