In 2018, Colin O'Brady made a grueling solo crossing of the Antarctic landmass, hauling a 300-pound sled for 54 days over more than 900 miles with no resupply or, he contends, assistance. Yet what constitutes assistance has spawned a chilblain within the adventurers' community, starting with his book's title, "The Impossible First."

"First" signals that an unsupported, unassisted crossing had never been done. Others say such a "first" is yet to come — or has already been done. Even National Geographic, which raptly followed O'Brady's journey, recently excised the word "historic" from its website's initial headline, which now reads "Explorer completes Antarctic trek," after new reporting "uncovered important details" regarding the claim.

O'Brady has said he's "stunned" by such blowback. That's understandable. His accomplishment (which became an unplanned-for race when the world learned that Briton Louis Rudd was pursuing the same feat) inspires awe, and his account of the trek is a compelling mix of bravado, fear, self-doubt, dream states, exhaustion and adrenaline. He's a good writer.

The controversy revolves around his (and Rudd's) choice in the last days to follow the South Pole Overland Traverse, on which snow tractors pull great bladders of fuel to the pole along a route mapped to avoid crevasses and marked with flags — a use that came to light when one of O'Brady's Instagram posts showed tread marks in the snow.

While reticent for months, O'Brady explains in his book that he was pretty much ordered to take the route by Antarctica Logistics and Expeditions for safety reasons or they could not rescue him, if needed. (In its further reporting, National Geographic notes that ALE disputes this account.)

Rudd has said that the route actually was so rutted that he skied alongside it. (His book is due this summer.)

“The Impossible First” by Colin O’Brady

Yet does even being near such a marked route constitute assistance? Critics say that if Norwegian Borge Ousland's solo coast-to-coast crossing in 1997 was negated because he sometimes used a kite to catch the wind, then using a graded route also constitutes assistance. The fact that almost no one in their right minds (and with the right fundraisers) would attempt such feats, much less achieve them, gets lost in the social media static. (The role of daily social media posts also is a flash point among the critics.)

O'Brady, by any definition, loves a challenge. He owns the speed record for the Explorers Grand Slam — climbing the highest peak on each continent and skiing the last degree to the North and South Poles, which he did in 139 days in 2015. He recently was part of the crew that rowed the treacherous Drake Passage from Chile to Antarctica.

While such achievements can prove lucrative on the speakers' circuit, he also is passionate about inspiring children to know they can do more than they think possible. There's likely no definitive verdict to be had here, pitting transparency against tenacity.

Kim Ode is a former features writer for the Star Tribune.

The Impossible First

By: Colin O'Brady.

Publisher: Scribner, 279 pages, $28.