Messenger arrived on Inisheer in the late 1950s with the tools of an American cultural anthropologist - notebooks, a tape recorder, a hypothesis. The island in those years had about 350 people. Most spoke Irish at home but mixed in English when it suited them. The economy ran on subsistence farming and fishing from canvas-and-tar canoes called curachs. The Gaelic Revival had cast islands like this as living museums of authentic Irishness for half a century. Messenger thought the picture was off.

He spent two years interviewing islanders, attending mass, walking the limestone pavement, and watching how families moved through their days. He counted: eleven of the 111 adult men and nine of the 85 adult women had abandoned traditional dress for mainland styles. The use of the curach had dropped sharply - from thirty or fifty three-man crews fishing year-round in the early 1900s to nine crews in 1960. Almost everyone older than eight spoke fluent English. Some islanders even confessed to their priests in English. The romanticised picture of monoglot Gaelic peasants, Messenger argued, was outsiders' projection.

The chapter that made the book infamous - and that has marked it ever since - was about sexuality. Messenger reported that islanders had no formal sex education, that intercourse was discussed as a duty to be endured, that any display of sexuality from childhood onward was punished severely. He wrote that menstruation and menopause were spoken of with dread, that one elderly woman had taken to her bed to avoid the supposed madness of menopause, that women asked Messenger's wife about basic reproductive biology because there was nowhere else to learn.

It is worth pausing here. These were real people, identified to themselves and their neighbours even if anonymous in print. Messenger published things that the islanders had told him in private, sometimes shamefully. Whatever the truth of his observations, the people he described did not get to write back. The book sold widely in American sociology and sexology classrooms throughout the 1970s. Generations of undergraduates read about Inisheer's intimate life with no input from anyone who lived there. Some islanders learned of the book years after publication and felt betrayed by it - a feeling that lingers in family memories on the Aran Islands still.

The historian David Fitzpatrick of Trinity College Dublin took on Messenger's work most pointedly. Writing in Marriage in Ireland, a collection edited by Art Cosgrove, Fitzpatrick called Messenger's account "highly coloured" - one of several American anthropological studies of Irish rural life that he found exaggerated. Fitzpatrick pointed out that Irish post-famine sexual restraint was not unique to Ireland but was common across European peasant societies. If Irish rural sexuality was sick, he argued, so was rural Europe.

Other scholars have raised related objections. The sample - 350 people on a small island, observed by two outsiders for two years - was thin. Messenger was a self-described participant observer, but his Catholic-American conservatism may have led him to project unfamiliar Irish Catholic rural mores as pathology rather than difference. Subsequent fieldworkers found island life more varied than Messenger's monochrome portrait suggested. The flat declarative paragraphs in his book had given way, by the 1980s, to a much more skeptical academic literature.

Inis Beag occupies an awkward place in the canon. It is too widely cited to be quietly dropped. It is too questionable to be treated as straightforward ethnography. Modern teachers introduce it with the framing it deserves - as a document of mid-twentieth-century anthropological assumptions as much as of the place it claimed to describe. Messenger himself returned in 1989 with Inis Beag Revisited, partly in response to criticism, partly to reflect on what participant observation actually delivers and what it misses.

Inisheer, the real island under the pseudonym, has changed since the 1960s. Population dwindled to 257 by 1979 and has recovered to 343 in 2022. Tourism is now the main industry. Aer Arann Islanders rattle in from Connemara Airfield several times daily. The ferries come from Rossaveel and Doolin. The limestone pavements are the same as they have been for ten thousand years. The people are not stuck in any anthropologist's notebook. They have lived through the half-century since Messenger left, and the island has answered him in the only way it could - by going on.