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The 1960s was a big decade for cannabis: Images of flower power, the summer of love and Woodstock wouldn’t be complete without a joint hanging from someone’s mouth. Yet in the early ’60s, scientists knew surprisingly little about the plant. When Raphael Mechoulam, then a young chemist in his 30s at Israel’s Weizmann Institute of Science, went looking for interesting natural products to investigate, he saw an enticing gap in knowledge about the hippie weed: The chemical structure of its active ingredients hadn’t been worked out.

Mechoulam set to work.

The first hurdle was simply getting hold of some cannabis, given that it was illegal. “I was lucky,” Mechoulam recounts in a personal chronicle of his life’s work, published this month in the Annual Review of Pharmacology and Toxicology. “The administrative head of my Institute knew a police officer... I just went to Police headquarters, had a cup of coffee with the policeman in charge of the storage of illicit drugs, and got 5 kg of confiscated hashish, presumably smuggled from Lebanon.”