Image: 1939 UK ad in unspecified magazine from https://www.gracesguide.co.uk .
Nescafé was rolled out in UK and USA. It was first available in Europe a few years earlier. We couldn’t find a 1939 era U.S. ad.
Various kinds of instant coffee were developed as long ago as 1771. The process developed to make Nescafé in the late ’30s became widely popular because of taste improvement. Learn more at http://www.historyofcoffee.net/coffee-history/instant-coffee-history/ .
See more about Nescafé here: http://www.nestle.com/investors/brand-focus/nescafe-focus .