Raymond Howgego's prodigious Encyclopedia of Exploration looks more like a topographic feature than a set of books. Its four gigantic tomes chronicle the history of world travel and exploration, from ancient accounts inscribed on Babylonian clay tablets to the 1982 mapping survey by a group of intrepid English schoolboys and their teachers of Inaccessible Island, a precipitous speck in the far South Atlantic Ocean.
The publication of Part 4: 1850 to 1940 (Continental Exploration) completes Howgego's epic 15-year odyssey. So what did the physicist-turned-scholar learn along the way? What - to borrow the perennial question posed to every traveller upon return - was the best bit?
"One of my favourite travellers ... is the medieval Moroccan Ibn Battuta, who makes Marco Polo look like a stay-at-home," Howgego, who speaks - speed-reads, even - every European language (except Basque) plus Arabic "and some Farsi", says from his home in Surrey, England.
"About 30 years after Polo's return to Venice, Battuta travelled from Andalusia to China, Sumatra and East Africa. He returned to Morocco and then crossed the Sahara to Timbuktu on the Niger River. [He] also found time to make four pilgrimages to Mecca."
And Howgego's favourite explorer? "There are two I really warm to," he says. "Gertrude Benham intrigues me; she seems the most widely travelled of all women travellers. An English naturalist and mountaineer, in 1909 she was the first woman to ascend Mount Kilimanjaro. An extreme pedestrian, she later walked 5000 kilometres from Kano in Nigeria to Mozambique. She botanised, mountaineered and legged it around the globe from Tasmania to the Himalayas for more than three decades, but never wrote a book about her travels.
"I sleuthed Benham's travels from ships' passenger lists, her articles in obscure scientific journals and her recently declassified British-Indian intelligence file on her attempts to gatecrash Tibet in the 1930s."
Howgego also has a soft spot for the humanitarian Scot, Joseph Thomson. "In Africa, many expeditions received a hostile reception with volleys of gunfire, but during his years of African exploration Thomson never even pointed a firearm at an African," Howgego says. "He would defuse an armed confrontation with humour - by removing and replacing his false teeth or showing the warriors photographs of naked ladies."
Another favourite is the Chinese traveller Hsieh Ch'ing-kao, who, Howgego says, "provides a priceless lesson for the Euro-centred ego - he visited England in the 1780s, which he dismisses in his book as 'a sparsely settled island, separated from the mainland, with a large number of rich families'. As merchants and emissaries from as far away as Sri Lanka had visited Augustus' Rome, I wondered if the ancient and medieval worlds were more cosmopolitan than we think."
Such tales are, he says, one of the reasons the Encyclopedia is about exploration, not European discovery. "After all, how can an 18th-century Dutch or English navigator claim to have discovered a continent that's been inhabited for 30,000 years?" he asks. "I've tried to make it non Euro-centric."
Much of Part 2: 1800 to 1850 is devoted to Australian exploration. "I was fascinated by white Australians' collective delusion of a great inland sea," he says.
"That search became [the Australian equivalent of] the quest for the source of the Nile or the Northwest Passage.
"Charles Sturt optimistically included two seamen and a whaleboat in his 1844 expedition and pursued the myth to the edge of the Simpson Desert.
"A few years later Leichhardt and his companions set out westwards from the Darling Downs for the Swan River - and vanished without trace - not even a belt buckle or horseshoe were found.
"More than 150 years later, Patrick White's Leichhardt doppelganger Voss still haunts Aussies. Yet some of the lesser-known Australian explorers I've included in the Encyclopedia aren't even included in the Australian Dictionary of Biography."
Howgego writes with panache and wit and seems to relish the idiosyncratic - such as the Japanese Buddhist monk-turned-polar explorer Nobu Shirase, rather than better-known heroes of the British Empire like Ernest Shackleton and David Livingstone.
"Lethal icebergs prevented Shirase's 1910 expedition from landing on Antarctica, so he turned his ship around and sailed to Sydney where, to the delight of its newspaper cartoonists, he erected the prefabricated Antarctic winter hut at Parsley Bay on the shores of Sydney Harbour.
The following year they managed a landing and penetrated 282 kilometres across the Ross Ice Shelf.
"Before departing Antarctica for Yokohama, South Pole conqueror Roald Amundsen came aboard the Japanese ship for a chat, but language difficulties limited it to 'nice day' and 'plenty ice'."
Howgego has also has a "rich list" of favourite traveller explorers. "There's the dotty American entrepreneur George Train, who made his fortune from ... yes, railroads," he says. "Despite strong evidence to the contrary, Train believed himself to be a genius and delighted in breaking his own round-the-world speed records in chartered steamers and trains. His 1890 record of 67 days stood for a few years. But he often got derailed along the way and ended up in jail. He claimed another record in having been inside a total of 15 jails."
Even that achievement is overshadowed by the British who, Howgego says, could well have been the inventors of travel as comedy.
"The wealthy English 'sportsman' St George Gore could have stepped out of a Monty Python skit," he says.
"In 1854, the baronet arrived on the American frontier with a huge arsenal of weapons and a cavalcade of servants, cooks, his valet, a personal trout fly-tier and a pack of foxhounds.
"Teaming up with legendary frontiersman Jim Bridger, who acted as guide, Gore shot buffalo and deer in such vast numbers he nearly triggered a Sioux uprising."
The quietly spoken travel scholar is himself a serial traveller. He was packing his bags when we spoke and was flying out in a few days to one of his favourite destinations, Ethiopia. "I want to follow up some of the Slovakian travellers' accounts I translated in Volume 4."
Iran and western China are also of special interest. "Kashgar has been the centre of my universe - I hope the extension of the railway hasn't changed it," Howgego says.
"And there are several more Zoroastrian temples in northern Iran I want to visit." He has the amiable enthusiasm of an academic version of Michael Palin.
With a nod to travel liars and perhaps to give reviewers sleepless nights, Howgego has seamlessly embedded a spurious explorer in Part 1 - not even the copy editor or publisher have been able to spot the fictional traveller.
Sydney antiquarian book dealer Hordern House is offering a reward of a case of champagne to the first reader who unmasks this mystery impostor.