His Last Trip : Albert Hofmann, the Swiss chemist who discovered the mind-altering drug LSD, has died at the age of 102. Associated with the hippy counter-culture, the hallucinogenic drug's medicinal properties as a treatment for mental illness were advocated by Hofmann, even after it was widely banned.

His research into crop fungus in the 1930s is behind LSD's emergence. Several years into the study, he inadvertently became a human guinea pig, accidentally experiencing the effects of the drug.

"I had marvellous visions," he recalled. "I was thinking in colours and pictures and then it disappeared and I said to myself that I must have mixed something up in the laboratory."

Former Harvard lecturer Timothy Leary popularised LSD with his "turn on, tune in, drop out" message in the 1960s. But its reputation took a turn for the worse amid fears it could cause long-term psychological problems.