Lefax was a company founded in 1910 by J. C. Parker in Philadelphia that produced a range of personal organisers. In its early days, the biggest customers were power plant engineers whose technical handbooks had grown too big to carry. In 1921, a London printer and stationery marketer, Norman & Hill Ltd., began importing the organizers, called Lefaxes. Several years later, they began to make the personal files under their Filofax brand. The Lefax trademark was registered 5 October 1926. Its use in the engineering industries was so pervasive that some journals were published in Lefax format.