Having exchanged contracts with Monk's manager, Scher rang the man himself at the club where he was playing in nearby San Francisco on the Friday before the concert – and discovered Monk knew nothing about it. Scher explained the situation and patiently whittled away the obstacles, including volunteering his older brother to pick up Monk and the band, and return them to San Francisco for their evening show.

So on the Sunday the disbelievers witnessed a car arrive with a double bass sticking out of the window. "As soon as they saw Monk get out, they lined up, bought tickets, and the show sold out," says Scher. Although his motivation was less about healing wounds than wanting everyone to hear a genuine genius, the event, nonetheless, represented a much-needed truce between blacks and whites.

That was not the end of the story, however. Scher put a tape of the concert in a box with a poster and a signed program, and there they stayed – for 35 years. When he rediscovered them he had the tape digitised, and told jazz saxophonist Jimmy Heath about it. Heath connected him with TS Monk, Thelonious's son, and they arranged to meet.

"I showed him the program," Scher recalls, "and his wife said, 'Oh look at this: another phony Monk signature.' TS took one look at it and he said, 'Oh, no, honey. This was how he signed his name when he was really feeling good.'" The recording confirmed TS's instinct. "I've listened to Monk my whole life," Scher says, "and the energy was definitely several degrees up from what I would hear on [studio] recordings."

It's taken another 15 years from the meeting with TS for this exciting addition to the discography to see the light of day. When you think that Monk spent two thirds of his career being considered ahead of his time, and the rest being yesterday's man, Palo Alto, made with saxophonist Charlie Rouse, bassist Larry Gales and drummer Ben Riley, offers fresh confirmation that his genius was still flowering in 1968.

Palo Alto is released on September 18.