We are all familiar with picture books, but their form and what it means to read them are not simple matters. Are they books or manifestations of narrative visual art? Which terminology should we use when discussing them? Should we take note of what children make of them, and how relevant to our attempt at understanding them is the regularity with which they are used to teach children how to read? How have they come to be the way they are?

David Lewis resists easy answers to these and many more questions. He enlists two six-year-olds, takes note of what they tell him, and insists on the importance of keeping an open mind as to what a picture book is.

The first half of his book is largely about the formal features of picture books; in the second half his emphasis shifts towards an examination of the ways in which readers and contexts influence their shape and form.

Described by its author as eclectic and possibly eccentric, Lewis’s book is, for the reader, like accompanying a reflective guide on an exploratory tour of a territory that proves to be vaster and much more intriguing than many travellers might have envisaged. It’s a real “teaching” text, with the author’s voice coming across clearly: musing, explaining, insisting upon and restating matters, and occasionally sounding mildly critical.

After a brief review of a selection of picture books intended to demonstrate the diversity inside individual covers, Lewis makes his own contribution to the debate on how best to describe the crucial interaction of word and image. The vivid metaphor he offers is that the words and pictures are two strands held together in an ecological relationship.

As Lewis explains, if we say that words and images in picture books interact ecologically, that the book acts as a kind of ecosystem, then the words come to life in the context (the environment) of the pictures and vice versa.

We are encouraged to see how they act upon each other reciprocally; the ecosystem as dynamic structure helps us to understand how word-picture relationships might be continually shifting and changing; the recognition that ecosystems can be complex as well as flexible helps us to appreciate the heterogeneity that we sometimes find in a picture book.

The ecological analogy can be extended to encompass the picture book as it comes to life during what Lewis calls the “reading event”.

Following his account of the picture book form, which includes the effects of technological developments, social and cultural changes, and artistic innovation since the mid-20th century, Lewis explores the special relationship that exists between picture books, the child reader and the concept of play. He then expands - in a chapter which will be well thumbed in training college libraries - on the playfulness inherent in approaches to rule-breaking and subversion, which sets the form within the context of the wider contemporary culture.

Lewis describes post-modernity’s defining features and provides some examples of how these features have influenced writing for adults before turning us to an account of the ways in which some picture books might qualify as post-modern. He also offers a short introduction to Gunther Kress and Theo van Leeuwen’s book, Reading Images: the grammar of visual design. Although this work does not encompass sequential narrative art, it’s a rich source for anyone who is interested in picture books and, in an appendix, Lewis gives a further demonstration of how the most useful aspects of the “grammar” might be applied to picture book images.

Lewis concludes by tackling the question of how picture books come to possess meaning. He offers a new perspective, via the insights he has gained from the work of Ludwig Wittgenstein. The philosopher recommends the practice of looking closely and only then thinking about what you find. Lewis does just that, ditching preconceptions, taking nothing for granted, and encouraging us to do the same.