Shulgin's work had nothing to do with weed, addictive drugs or getting a body high.
He invented and classified an entire new spectrum of chemicals closely related to the brain's chemicals such as serotonine. He tried to synthesize every possible combination, moving the amino groups around, substituting existing compounds with allyl or methoxy groups, and experimented with all these chemicals on himself with precise procedures to ensure his safety. These chemicals have proven to be extremely powerful consciousness-altering drugs, active at just a few milligrams, producing profound mind-bending effects and providing an unparalleled insight in the inner workings of the mind and its chemical balance.
He has provided the public with detailed descriptions of these chemicals, both synthesis and their subjective effects. He never profited financially and risked his life and freedom many times just to chase this knowledge. (And have great sex, as he states in his books). Alexander Shulgin was a genius, and the way society is developing there will probably never be a man like him again.