Iona Opie (1923-2017) and Peter Opie (1918-1982) were a husband-and-wife team researching childhood folklore. They started their work in the 1940s, when the birth of their first child sparked off their interest in nursery rhymes. Over more than four decades, they extended their research into many other areas of children’s culture, including children's literature, play and games, children’s language, customs, beliefs and superstitions.

The Opies were avid collectors, and over the decades amassed one of the world’s largest collections of children’s books and printed ephemera, covering children’s literature from the 16th to the 20th century. The Opies' collection of children’s literature – over 20,000 pieces – was donated to the Bodleian Library in 1988.

However, in researching children’s culture, the Opies not only relied on books published for children. Instead, they also wanted to collect the oral traditions of childhood – the rhymes, songs and games, the language and customs of the playground – and in doing so, they took the approach of the collecting these from the children themselves.

In November 1951, the Opies placed an advert in The Sunday Times, seeking help from teachers in collecting children’s lore and language - the idea being that schoolchildren would answer a set of questions about their counting out rhymes, local superstitions, cheers, slang and abbreviations, and the teachers would then send the replies to the Opies. Over the years this method evolved into encouraging the children to freely describe their games and playground activities, hobbies and preferences. From the 1950s through to the 1990s, the Opies received thousands of replies from children from schools all over the UK, often with accompanying letters from the teachers describing the local playground culture from their perspective, and sending in school journals, photographs, newspaper clippings and other background information. With some of their correspondents, the Opies stayed in touch over years, allowing them to trace the development of games and playground crazes at a particular school or in a particular area over time.

To process their data, the Opies developed a daily work routine at their home in West Liss, Hampshire: Iona Opie would sort and analyse the incoming information and compile working materials, adding survey responses, secondary literature and bibliographical notes. Peter Opie would then write up the results in a first draft, on which Iona Opie would comment on the basis of her data, and so on. This produced an ever-expanding system of working files, each one relating to a particular game, activity or custom. Iona Opie's meticulous approach to data management was crucial to keeping physical and intellectual control of the complex and extensive collection of research material.

Neither of the Opies had an academic background, as they were very much private researchers and authors, not associated with any academic institution. However, the Opies published more than 20 books – anthologies of traditional nursery rhymes, songs and fairy tales, as well as observations and analysis of children’s play and games in the street and in the playground, and the lore and language of schoolchildren - which were critically acclaimed for their contribution to folklore and childhood research, as well as being popular with non-academic readers. Amongst many other honours and awards recognizing their work, Iona and Peter Opie both received honorary MAs from the University of Oxford in 1962.

After Peter Opie's death in 1982, Iona Opie continued to work on the many books that were still projected, before retiring in the 1990s from more than 50 years of childlore research.

cf. Opie, Peter Mason (1918-1982) in Oxford Dictionary of National Biography.