Classified, By HG Cocks

Classified's cover – of a man peeking teasingly over the top of a newspaper of social ads – suggests that we're in for a racy read. What HG Cocks actually gives us is a serious survey of society's changing attitudes towards sex, relationships and matrimony as seen through the personal ad. With more single people in Britain than ever, Cocks argues this – and its modern equivalent, the internet profile – still has a job to do.

In 1922 the Daily Mirror was already proclaiming, "if you don't advertise yourself nobody notices you". And what a long way self-advertisement has come since then, from something slightly shameful and anonymous to an activity most under-thirties take for granted. Social networking sites demand disclosure, not discretion.

Cocks takes in everything from correspondence clubs to internet dating sites, back to the matrimonial ads of the late 17th century. A young man in 1750 made no bones about wishing to alter "his condition, by marrying a young lady (or Widow who has no child)" who could make a settlement of £8,000 to £10,000. By 1900, there were 25 newspapers helping singles to find spouses. Battalions of lonely soldiers in their trenches placed companionship ads. Breezy communication was wanted and it seemed patriotic to provide it. However, the resulting deluge of letters overwhelmed the Army's postal system. One single soldier received 3,000 letters and two sacks of parcels. With national security also at risk (what if some female pen-friends were enemy agents?), the government banned such advertisements.

The most interesting part concerns Alfred Barrett, a former Family Circle editor who in 1915 established a lonely-hearts magazine, The Link. It offered free advertising but also – a novelty – introductions to subscribers. All went well until 1920 when the small print came under scrutiny. "Sporty" girls requesting "chums" weren't dubious. But "artistic" men seeking same-sex friends were - especially when describing themselves as "intensely musical", and questing after a "manly Hercules". The Link was suppressed after police arrested a fraudster carrying letters from his male lover, whom he had met via the magazine's columns. Barrett was imprisoned for corrupting public morals.

Some of Cocks's material is rather dull, unless you find fascinating the complications of peddling "dirty" books. Meanwhile, calling the personal column a "vital resource" seems overstated. The classified ad appears not so much subversive as suburban. During the 1960s the police targeted underground publications, suspected of printing ads by prostitutes and homosexuals. What they found were mostly office managers, middle-aged ad execs and would-be wife-swappers from Middlesex. Somehow, that says it all.