Henry Dreyfuss (1904-72) was one of the United States’ most influential industrial designers of the 20th century. As well as being immensely practical – functionality was key for him – and productive, he was a design theorist.

His book The Measure of Man (1960) shows how he studied the human body to make his products more usable – he was ahead of his time in his understanding of ergonomics. In the 1930s he was commissioned by Bell to design a telephone. His Model 302, which was rolled out across the AT&T phone system in the US, in many ways set the template for decades of what a telephone was supposed to look like.

Satisfying click

It had a square base and a handset with ear and mouthpiece that sat in a cradle with a satisfying click. A dial for numbers dominated the front of the base. While working on his design he dressed as an AT&T repairman so he could visit homes, to see what problems consumers were encountering with their existing phones.

Originally, 302s were made in black-painted metal until shortages during the second World Ward saw it being made in heavy plastic. It is estimated that by the 1950s, when the 302 was replaced with an updated design, 250 million had been sold.