Wikipedia is mis-informed:
Patent US3200819 - Smokeless non-tobacco cigarette
In 1963, Herbert Gilbert patented "a smokeless non-tobacco cigarette". In his patent Gilbert described how his device worked, by "replacing burning tobacco and paper with heated, moist, flavored air." Gilbert's device involved no nicotine, smokers of Gilbert's device enjoyed flavored steam. Attempts to commercialize Gilbert's invention failed and his product fell into obscurity.
However, it deserves a mention as the earliest patent for an electronic cigarette.
Better known is the the invention of Chinese pharmacist Hon Lik, who patented the first nicotine based electronic cigarette in 2003. The following year, Hon Lik was the first person to manufacture and sell such a product, first in the Chinese market and then internationally.