Wikipedia
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.
In the 1980s Lefax was bought out by London Wood Partners, a British firm, and in 1992 the company was acquired by its rival, Filofax. The original intention was that Lefax would be Filofax's top of the line range but the Lefax brand was eventually phased out.