Dunedin's Bill Denz was, as the title of his biography states,Bold Beyond Belief.

While "New Zealand's mountain warrior" was not needlessly foolhardy, it was a wonder he even made it to his 32nd birthday. With relentless drive, he pushed himself up places and in conditions where others would not dare to venture.

When a relatively small avalanche buried and killed him as he walked back to a lower camp on the slopes of the Himalayan giant Makalu in 1983, it was almost anticlimactic considering the dangers he had so often faced.

Wellington builder, climber and author Paul Maxim is awed by some of Denz's feats of endurance and determination. He devoted three years to researching Denz and has produced a 300-page book in which that admiration is interwoven with recognition of his subject's flaws.

These, including his apparent self-centred attitudes and prickly manner, could make him unpopular.

Many an older climber, while respectful of his achievements, has mixed memories. The tribute from American climber Greg Child, one of many Maxim includes, is especially blunt.

"The Bill Denz I recall was a man who was self-sufficient, stoic, complex, reticent, intense, ambitious, competitive, steel-willed, fiery, fearless, undemonstrative and selfish.

These are the attributes of the classic alpinist." Shortish and stocky, he lacked the rangy build of the archetypical rock climber - and it is acknowledged he was never the greatest "free-climber".

But his strength, courage and bloody-mindedness made him a formidable figure in New Zealand and around the world. Some of his later solo efforts were simply staggering.

Maxim provides the family and community context for Denz growing up in Dunedin where he attended Kaikorai Valley High School. He was in the army for a time and, later and briefly a juniorOtago Daily Timesreporter.

Thanks to Maxim turning over almost every rock and, notably, the detailed and personal letters sent home to his mother (Denz's father died when he was only 8), insight into Denz's life and character is beyond what one might have normally expected.

His peak accomplishments around Mt Cook, in Fiordland's Darran Mountains, Alaska, South America, the Himalayas and the big rock walls of the United States are all examined, although many readers, including me at times, may find blow-by-blow climbing information in some of these chapters too exhaustive.

Maxim also recognises that Denz was of the generation able to take advantage of the new curved picks on ice axes. They opened up fresh ice-climbing possibilities.

It was an era as well, with Denz in the vanguard, when many climbers were pushing the limits, so much so that death among the sport's elite was commonplace.

He and his first wife, Christine, in the few years they were together lost 13 friends killed in the mountains.

Denz seems to have taken the fatalities, bar one, as an occupational hazard you just had to live with. A chapter called The Kamikaze Kid focuses on that exception, Phill Herron, a fearless Dunedin climbing prodigy. Herron, on a New Zealand expedition to Patagonia, South America, with Denz, died down a crevasse aged 19.

Herron, who soared towards the top from age 17, exuded easy-going charm and cheerfulness and was naturally athletic, in many ways an opposite to his close friend Denz. But the pair plus skilled rock-climber Murray Judge, now an Oamaru GP, formed a formidable complementary partnership to pioneer rock-climbing in the Darrans.

Herron's death left Denz emotionally shattered and, for a period, disillusioned with mountaineering.

The book includes lists of Denz's climbs, a glossary for non-climbers and notes for sources but no index.

Maxim has said he declined possible options from two mainstream publishers, using his Maxim Books imprint instead. He wanted to include more material and photographs than suited commercial houses.

Maxim did receive some financial support from the clubs that Denz, although hardly a typical club man, was associated with; the New Zealand Alpine Club, the Otago Tramping and Mountaineering Club, the Canterbury Mountaineering Club and Federated Mountain Clubs.

Primarily, though, it was the full co-operation from the Denz family and from friends, associates and many climbers that underpins this important contribution to the story of New Zealand climbing.

Maxim has done them all - and tough and tenacious Bill Denz - proud.