away". It takes patience and the requisite reassurances to learn the extent to which this characteristically stiff-mannered Swiss scientist is haunted by his own legacy.

"LSD has phenomenal power to do good," he says. "We were like explorers in the human mind, full of wonder but careful where we trod. It was never meant to be taken for pleasure. Those people betrayed us."

By "those people", Hofmann means the riders of the great psychedelic wave that broke over popular culture in the 1960s with LSD as its lodestone and with the likes of the Beatles, Ken Kesey and Timothy Leary, the maverick acid apostle, as its godheads.

Hofmann was in his late thirties and doing routine work on plant compounds for a Basle chemical company when he first synthesised lysergic acid diethylamide from ergot,

a poisonous black fungus that often grows on rye.

In the spring of 1943 he accidentally ingested a minute trace of the chemical and, intrigued by the peculiar feelings that resulted, decided to conduct a controlled experiment. Three days later he gave himself a 0.25 mg dose of LSD, then got on his bicycle and pedalled home. The grey streets of wartime Basle weaved and feinted around him and a kaleidoscopic lightshow exploded in his head. "A demon had invaded me, had taken possession of my mind, body and soul," he wrote.