It started out small and modest: in February 1884, a slim paperback book hit the shops, bearing the title The New English Dictionary on Historical Principles and costing a hefty twelve shillings and six pence. Within, it contained all the words in the English language between A and Ant.

This book was the product of five years' work by James Murray and his numerous contributors and the first volume in one of the most ambitious academical exercise ever undertaken, The OED.

The intention was to record every word used in the English language since 1150 and trace it back through all its changing meanings and different spellings through the ages. It was decided that there should be at least one citation for each century of its existence - oh, and at least one for each meaning as well. This was a momentous task to say the least. To achieve these aims, every major piece of English literature from the last seven and a half centuries would have to be read through and carefully indexed.

The man chosen to lead the project, James Murray, initially had wildly optimistic ideas about the daunting task he had reluctantly agreed to do. He thought the whole project would cover about 6400 pages and take no more than eleven years to finish!

Five years down the road, when Murray and his crew had only just reached the word "ant", they realised it was time to reconsider the schedule. As we now know, the project actually took over four decades and easily fills 15 000 densely printed pages.

Dr William Minor mentioned above was by no means the only contributor Murray had, although he is probably the most famous. Hundreds of volunteers (among them the eccentric James Platt, who was said to master a hundred languages) helped with the research, sending in definitions and citations from all over the world. Even Murray's eleven children were, almost from the moment they had learned the alphabet, roped into the endless business of helping to sift through and alphabetize their father's huge hoard of paper slips, on which were recorded seven centuries' worth of philological history.

Murray worked on his dictionary for 36 years, from his appointment to editorship in 1879 to his death in 1915. He was working on the letter U when he died, but his assistants took over the work and kept going for another thirteen years until the final volume, Wise to Wyzen, was published in 1928. (Volume 12, XYZ, had appeared earlier, for unclear reasons.)
B. Bryson: Mother Tongue (London, 1999)

Thanks for Cletus the Foetus for some proofreading.