Discovery: Dinosaurs. By Dougal Dixon. Ladybird.

What were we looking for? At the very least, accuracy - and this helped us weed out the stragglers early on. Howler-spotting was an entertaining warm-up exercise for the judges, and we found plenty of material: fish with four limbs, squids with six arms, and an astronaut whose mass changes while his weight remains constant. Next, clarity: not to be confused with over-simplification, a pernicious trait often to be found in glossaries (for example, in a text on ice-cream, “Arabs: Arabs are people who live in the part of the world called Arabia.”) We were looking for texts where we could see through the surface features, the lavish artwork and the specialised vocabulary, to the bony principles that hold a book together. We wanted to be able to see past the detail to the big concepts; we searched for an understanding of the relation between function and form, an insight into how things hold together and how animals work, for answers to “Why?” questions rather than extracts from the Guinness book of fascinating facts and figures.

The “isn’t-nature-wonderful” approach was a criterion for rejection; we wanted a book with signs of some epistemological self-awareness. Where does all this knowledge come from? What are its limitations? And on top of all this, we wanted children appeal. Would the text turn them on?

So finding the winner was easy. Dinosaurs by Dougal Dixon, in the Ladybird Discovery series (Pounds 2.99), passed all these tests and more.

First, one of the judges, who had, serendipitously, both expertise and a strong affection for the topic, checked for accuracy. Next, we noted the motivating effect of the author’s own enthusiasm for his subject. It permeates every page but does not obscure the narrative line as the grand procession of beautiful multicoloured beasts marches past.

We were specially taken by the explanatory boxes, set within the text, containing simple diagrams of how each dinosaur body-type was, as it were, assembled. Longitudinal sections show how head, body, legs and tail balance and support each other. These diagrams, we judged, would be the starting place for creative and enthusiastic teachers using the text. They call out for investigation and experiment, for transformation into three-dimensional models. If there had been some papier mache and old toilet rolls available, I think the judges might have started cutting and sticking on the spot.

The surrounding text is strong on explanation, comparison, sequence and process. There are references to our current ignorance and working hypotheses, and there are dozens of poly-syllabic wonders to roll round your tongue, like the Chinese Stegosaur Yingshanosauras, and the dinosaur with the longest name Micropachycephalosaurus. In short, it’s a winner.

Two other books deserve honourable mentions. Caring for our Environment, an Oxford Reading Tree Fact Finder (Pounds 2.50), was head-and-shoulders the best of the numerous environmentally-conscious entries. Its strength was in its scale: small, local, limited and manageable. Two headteachers from a village near Edinburgh describe how the children of the local primary school developed their “Take Pride in Pumpherston” project. They cleaned up the pond, planted trees, built window boxes, and campaigned for safer roads. And then they wrote to the “people who helped us” to say thank you.

For all its impeccable correctness, this text could make a good starting point for a primary school or class planning a similar project. A little more attention to local planning procedures might be desirable, although this might not make for quite such an easy read. “We decided to paint a special mural on the wall,” for example, qualifies for penalty points in the over-simplification category.

Finally, we admired Ecosystems, a unit from the Stage Two Science series, produced for Channel 4 Schools by Granada Television (Pounds 5.95). This scored points for complexity, and the use of substantial passages of explanatory text.

Children in primary schools do not need childish texts. If their science teachers are worth their salt, the pupils will be hungry and thirsty for difficult concepts and arguments. And this text has plenty of those; what is more, the authors keep their eye on relevance, so that the inevitable sermon on rain forests is balanced by material on pollution in the school, sewage and water treatment, and a pupil project on dustbins. It is beautifully illustrated with crisp black and white pen drawings, and, for those long Friday afternoons when even environmentally conscious science teachers have run out of steam, there are some wonderful detailed pages for colouring-in. This is not science of course, but the children will love it.

Mary Jane Drummond is a tutor in primary education at the University of Cambridge Institute of Education. The other judges were Paul Black, emeritus professor of science education at King’s College, London, and James Williams, head of the science faculty at Beacon School, Banstead, Surrey, and a council member of the Association for Science Education. The same panel judged the secondary award