The world of children's games remains one of the few places where children can gloriously be themselves, free from the conformist and sanitising tendencies of adult supervision. It is a totally anarchic domain, with its own bizarre rituals, rhymes and chants, untainted by notions of political correctness.

The Opies, in their previous journeys into these private territories, have shown a remarkable ability to blend scholarly research with an enthusiasm which can only be called childlike, resulting in studies such as Children's Games in Street and Playground and The Singing Game. This new volume brings this ambitious and comprehensive survey to a triumphant close.

Classifying "games with things" as those pursuits where the objects used provide the primary reason for the games, the authors embark on an exploration of the origins and development of such childhood playthings as marbles and knucklebones and activities such as hopscotch, skipping and ballbouncing.

With its erudite historical and literary analysis, the enterprise is, in part, an exercise in demystification; but the subject's essentially arcane nature is such that many mysteries remain tantalisingly unexplained. When, for example, children bounce their ball to the accompaniment of the words "One, two, three, alairy", they may be "repeating and enacting a Middle English term which was discarded by adults several centuries ago". But why should they be doing this?

The data which serve as starting point for the Opies' investigations come, in the main, from material collected in surveys conducted in the 1950s and 1960s, principally in Britain. Much of the fun and of the earthy richness of this lies in the linguistic diversity manifest in local and regional terms for the most basic objects and practices of play.

Of the scores of possibilities for "marbles", who could resist such delights as "balsers", "bullockers", "doggles", "doll edgers", "dummocks", "stonnac-kerools", "stubbers" or "tonses"? Or - still with marbles - who would not rejoice to know that in Edinburgh "A `pussie' or a `cattie' is a shot that's pushed and no right `plonked' (knuckled)"?

Most marvellous of all are the rhymes and chants which, for centuries, have been shouted by children, particularly in their games with ball and skipping rope. This idiosyncratic material, in which innocence and naughtiness combine in infinite variations, has claim to be the real children's literature, raw, surreal and subversive.

These verses frequently prefigure adult experiences, anticipating these with a mixture which is half fear and half fascination. Intimations of sexuality figure large, often as an obsession with knickers: "I'm a Girl Guide dressed in blue,/These are the actions I must do:/Salute to the captain, curtsy to the queen,/Show me fancy knickers to the football team."

In an age of channel-zapping and Net-surfing, the nagging worry must be that the traditional pursuits recorded by the Opies have only a limited life-span. Their own view is that "children will always play where they are on their own, in the freedom of an open space". We must make sure that these opportunities continue to exist.

Robert Dunbar has recently edited Enchanted Journeys: Fifty Years of Irish Children"s Literature