Book of a lifetime: Cyclopaedia, By Ephraim Chambers

As a historian of 18th-century London, it would be too predictable to choose Samuel Johnson's great Dictionary of 1775 as my choice for a book with enduring impact. There is no doubt that Johnson's work had a pivotal role in defining our modern language, but in terms of cultural significance, there's another book which is almost equally important: Ephraim Chambers's Cyclopaedia.

In the intellectual crucible of late 17th-century Europe, texts on science, astronomy, philosophy and the natural world proliferated, but many were too specialised for the ordinary reader. Gottfried Leibniz, a German mathematician and philosopher, described them in 1680 as "the horrible mass of books which keeps on growing". The same year, Ephraim Chambers was born in Kendal. Gifted but poor, he was apprenticed to a London mechanic, "but having formed ideas not at all reconcilable to manual labour he was removed from thence and tried at another business". This attempt also failed and "he was at last sent to Mr Senex, the globe-maker".

Senex globes are now prized for their astronomical accuracy, although his maps are equally prized for showing California as a large island. Ephraim was no ordinary apprentice; Senex, a man from Shropshire turned Royal Society Fellow and Freemason, was only two years older than his charge, making Chambers one of London's oldest apprentices at the age of about 34. Ephraim spent his time studying, and a friend noted that he left the apprenticeship "a very indifferent globe-maker". Instead, he had decided he was going to curate all the most important knowledge in the world. It seemed a crazy idea.

In 1728, his Cyclopaedia appeared, modestly subtitled, "An Universal Dictionary of Arts and Sciences". Chambers died in 1740, still working on another edition. The first edition of the Cyclopaedia reached Europe, where Denis Diderot was engaged to translate it. Diderot seized upon the material, adding to it from the burgeoning Republic of Letters, and it was published in 27 volumes from 1751 to 1772 as the famous Encyclopédie.

Diderot's Encyclopédie was suppressed at stages during its publication, accused of seditious content for asserting that knowledge and not social class or religion equated to true status. This monumental work was a core text of the Enlightenment, but it was inspired by a boy from Kendal, determined to write "the best Book in the Universe".

Lucy Inglis is the author of 'Georgian London: Into The Streets' (Viking)