Timed for the start of this year's crop-circle season, a new book from Lucy Pringle - the photographer who's been capturing images of the formations for nearly 20 years and who has become an international authority on the strange phenomenon - is a stunning visual chronicle of the increasing complexity of the patterns.

Already, two early crop circles have appeared this spring, one in Wiltshire, near Devizes, and another in Hampshire, Lucy's home county, and her book, Crop Circles: Art in the Landscape, whets the appetite further for what 2007 may bring in terms of new designs and increased wonderment.

In a series of amazing aerial photographs taken across the south of England, Lucy has anthologised the beauty and the mystery of formations going back to 1993, very many of them in Wiltshire which is well known for being the world "hotspot" for crop circles.

Acting on a tip-off from her network of circle-spotters, Lucy can be airborne within 45 minutes.

She usually flies in helicopters, but such is her dedication that "if a tin bath with wings was offered to me I'd probably be up in it", she told me.

And what does she expect in crop-circle designs this year?

"Each year we try to think ahead, but usually they are quite beyond our imagination," she said.

A founder member of the Centre for Crop Circle Studies, Lucy has the world's largest database of the effects of electromagnetic fields on both living systems and inanimate objects, such as cameras and laptops which often go awry at crop circles, and she is working with scientists worldwide to try to solve the riddle.

She admits that a few formations are man-made, but most defy rational explanation.

The geometry is so often "awesomely accurate", while human attempts have gaping errors.

"It's visual, it's measurable, it's tactile, it's there, and yet it's ridiculed and pooh-poohed by the majority of the media," she lamented.

Lucy is among those who believe that some form of radiation at the microwave level is responsible for causing the formations.

"But the big question is, how can we explain the extraordinary diversity of shapes that appear in the fields, and this is where we come to the ineffability of the whole subject," she said. "My belief is that there has to be an intelligence, a consciousness, behind this phenomenon, but what that could be is all conjecture."

There's no doubt that Lucy finds crop circle research a romantic adventure. "It's a subject that expands the mind - and heartens the spirit," she added.

As she writes in the introduction to her book: "Whatever the answer, these shapes show a superb elegance of line that touch the heart as well as the mind as they lead us into realms of mystery, along paths of fresh understanding, engrossing and delighting us as though brushed by the hand of God."

Crop Circles: Art in the Landscape was published yesterday by Francis Lincoln at ยฃ14.99. Signed copies are available from Lucy via her website www.lucypringle.co.uk or by emailing her at lucypringle@aol.com