The earliest e-cigarette can be traced to American Herbert A. Gilbert who, in 1963, patented "a smokeless non-tobacco cigarette" that involved "replacing burning tobacco and paper with heated, moist, flavored air". This device produced flavoured steam without nicotine. The patent was granted in 1965. Gilbert’s invention was ahead of its time. There were prototypes, but it received little attention and was never commercialized because smoking was still fashionable and the medical community’s warnings of the health risks associated with smoking were not fully accepted.