The market in popular history books might have the past for its raw material, but it is driven as much as any genre by the promise of something new.
Publishers and authors compete for our attention by promising astonishing new findings, racy behind-the-scenes tales, the untold story, what really happened.
But few authors have banked upon this method as effectively as Gavin Menzies, whose 1421: The Year China Discovered the World rode to best-seller status on a wave of controversy.
Having argued earnestly that Chinese fleets discovered and attempted to settle the Americas and New Zealand long before Columbus or Tasman, Menzies now appears with another forgotten fleet and another bold claim - with perfect commercial timing.
The key claim is spelt out in the subtitle, "The Year a Magnificent Chinese Fleet Sailed to Italy and Ignited the Renaissance". From gunpowder to astronomy to farming implements and mills, it is claimed that classical Italian scientists and artists worked largely from information and texts supplied by the officials of the Ming fleet, led by Admiral Zheng He.
There is much comparison of handpicked images and text from Italian and Chinese sources, aimed at conclusive persuasion of Chinese origin, and an in-depth probing of Leonardo da Vinci's work for Chinese influence.
Menzies' conclusion: that the Renaissance was not the rebirth of ancient Greek and Roman thought after all, but a flowering development of superior ideas and tools the Chinese fleet left behind. Taken at face value, the argument seems devastating. But 1434 suffers from the full range of logical errors that also saw 1421 pilloried by experts.
Although the six remaining accounts of the Ming voyages mention no travels beyond the Indian Ocean, Menzies still maintains that evidence of Chinese globetrotting is everywhere for the right observer - particularly various unidentified shipwrecks worldwide, which he interprets without fail as the remains of junks.
Leaps of logic made in 1421 become fodder for further extravagant guesswork. The most obvious explanations for the apparent Chinese connection with Renaissance thinkers - age-old overland links through the Middle East, for instance - are selectively plundered for support, or bypassed entirely.
For instance, the well-known population of Mongol slaves in Florence is used to prop up claims of a Chinese presence, although the sources Menzies quotes to add colour to his descriptions of Florence don't support his larger argument. And, more's the pity, 1434 doesn't even make the grade as a guilty pleasure.
It is a dull read, laden with flowery language and barely relevant diversions - more like the creaky textbooks that put you off history in the first place than a bold re-imagining of our Western heritage. The history is shaky at best, but even if all you demand is a thrilling tale regardless of accuracy, 1434 still lacks the spark of good storytelling that would make it fly. It is time to commend the 1421 franchise to the deep.
By Gavin Menzies (HarperCollins $36.99)
* Sam Finnemore is an Auckland reviewer.