Obituary for Louis Henry (1834-1913), a Belgian organic chemist who synthesized hundreds of new compounds in his lifetime. Henry notably coined the Henry reaction, which is today a classic carbon-carbon bond formation reaction in organic chemistry. Discovered in 1895, it is the combination of a nitroalkane and an aldehyde or ketone in the presence of a base to form β-nitro alcohols. The Henry reaction is a useful technique in the area of organic chemistry due to the synthetic utility of its corresponding products, as they can be easily converted to other useful synthetic intermediates.