When writing the book, Mr Walker was assured Morrie Shewan was the starter and it was Shewan's name that appears.
The programme for the meeting listed A (Alten) Nixon, and HM (Morrie) Shewan as starters.
Following the book's publication, Wanganui man Russell Sears and Julian Nixon, son of Alten Nixon, contacted Mr Walker to say it was Mr Nixon who actually started the race. Mr Shewan was the usual starter at the track but that summer he had taken an extended holiday.
"He was on holiday with his family in Taupo. It was the one regret in his life that, being the Wanganui club starter, he missed such an important race," Mr Sears said.
After the error was pointed out, Mr Walker found evidence of Mr Nixon being the starter, getting it from the International Amateur Athletic Federation in Monaco.
"Their archives person emailed me the application for a world record, a form that was completed after the run. It clearly shows that the starter was indeed Alten Nixon."
Mr Nixon now lives in Stratford and remembers the night clearly.
"All the crowd was around the starting line. I remember there were so many people around, when I actually pulled the trigger I wondered whether the athletes actually heard it."
Mr Nixon remembers the pace of the race was quick and Snell being overtaken by Great Britain runner Bruce Tulloh on the final lap.
Mr Nixon believes Tulloh's final lap challenge gave Snell a push and was the main contributor to Snell's record time.
That world record run is explained in chapter 19 of Mr Walker's book. "The 1962 population of Wanganui was 33,316. Reportedly, 18,000 spectators had gladly parted with their money in the hope of witnessing a new brand of New Zealand sporting history," Mr Walker wrote.
"Herb Elliott's world record of 3m.54.5s, set up on the cinders of Santry Stadium, Dublin, was under threat ... It was as if Snell had hoisted a large set of sails upon a favourable wind. He charged down the back straight of patchy grass."
-Peter Snell and the Kiwis Who Flew is in bookstores now.