Raphael Mechoulam, a pioneering Israeli chemist who is credited with opening the field of cannabis science after identifying the structure and function of the key compounds of cannabis, died on March 9 at his home in Jerusalem. He was 92.

His death was confirmed by the American Friends of the Hebrew University. Professor Mechoulam had been on the university’s faculty since 1966.

Professor Mechoulam’s groundbreaking work with cannabis began in the early 1960s, just before the use of marijuana and other drugs exploded in countries around the world, bringing seismic changes to popular culture while also kicking off decades-long battles about health effects and enforcement. His research earned him the unofficial title “the father of cannabis research.”

In the beginning, Professor Mechoulam’s fascination with marijuana was not cultural but scientific, driven by a fascination with the chemical structures of plants and other natural products.

At the time, he found the science of cannabis to be sorely lacking. “Morphine had been isolated from opium in the 19th century, early 19th century,” Professor Mechoulam said in a 2014 interview with Dr. Sanjay Gupta, the chief medical correspondent for CNN. “Cocaine had been isolated from coca leaves mid-19th century. And here we were, mid-20th century, and yet the chemistry of cannabis was not known. So it looked like an interesting project.”