Ludwig Josef Johann Wittgenstein was born in Vienna on April 26, 1889, one of eight children, to a rich and musical Viennese family which was of Jewish descent, but had converted to Catholicism. His father was a heavyweight in the steel industry, owning the largest Austrian company in the sector. It was not uncommon for private concerts to be performed at the Wittgenstein residence; Brahms' Clarinette Quintet was premiered there, and house-guests included Gustav Mahler and Bruno Walter. Ludwig's brother, the pianist Paul Wittgenstein, had pieces composed for him by both Ravel and Prokoviev.

Up until 14, Wittgenstein was educated privately at home. After a fairly undistinguished school career, first at Linz and then at a technical college in Berlin, he travelled to Britain in 1908 in order to do research in aeronautical engineering at Manchester University. Most of his time there was spent contructing and testing his own high-flying kite designs at the Kite Flying Upper Atmosphere Station, near Glossop, before he went on to design an early jet reaction propellor. But the mathematics involved proved to have a fascination of its own, and he developed an obsessive interest in the foundations of mathematics and logic. At the prompting of Gottlob Frege, he met with Bertrand Russell at Trinity College, Cambridge, in 1911. Recognising an extraordinary intellect and an exceptional student, Russell persuaded him to change his course and study mathematical logic, in which field Russell, one of its top exponents, said he "soon knew all I had to teach".

Under Russell's tutelage, during 1912 and 1913, he began the work that would lead to his early masterpiece, the Tractatus Logico-philosophicus. In 1914, apparently tiring of the self-congratulatory pretensions of Cambridge life, he left for Skjolden in Norway to work in more secluded surroundings, but his studies were interrupted by the outbreak of World War I. He returned immediately to Austria to enlist as an artillery officer and fought on the German side, seeing action both at the Russian front, where he won many distinctions for bravery in 1916, and in North Italy, where he fought as a member of an artillery regiment until 1918.

At the end of the war, he was captured by the Italian army and placed in a prisoner-of-war camp at Montessino. The completed manuscript of the Tractatus was found in his rucksack, and this became his PhD thesis after the Italians allowed him to send it to Russell by post (though it wasn't published until 1921). The book aimed at showing the limits of the propositional mode of thought and language, exposing the general character of representation, and examining the nature of logical truths, dethroning them from their place as the most general truths about the world, to see them instead as mere tautologies, though useful as forms of logical argument.

Having (as he then saw it) solved all philsophical problems, Wittgenstein retired from the field to become a schoolteacher in Lower Austria, which became his occupation between 1920 and 1925. He'd given away most of his considerable inheritance on the death of his father in 1913 (amongst others, the poets Marie Rilke and Trakl benefitted). His short career as a primary school teacher he considered a failure - he practised the methods of the Austrian School Reform Movement, which sought to engage the student's mind, rather than to submerge it in endless repetitive rote learning, and though he was popular with the children he taught, never reconciled himself to the other teacher at the school, or to the very different culture of the farming community it served. It's thought he seriously considered suicide on several occasions during this time.

He did a short spell as an assistant gardener in a monastery, and was then commissioned as an architect by his sister (Margaret Stoneborough) to design a large house, in Vienna, which kept him busy for a couple of years.

By the late 1920's, his thoughts were turning back to philosophy. Discussions (and, it is sometimes speculated, an erotic relationship) with the young logician Frank Ramsey who was to die tragically early in 1930, prompted him to return to Cambridge in 1929, where he was to lecture until the outbreak of the next war. His lecture material, ironically, was largely spun off from his developing critique of the position he put forward in the Tractatus. Notes of these lectures (1933 - 35) taken by some of his students, including J.L. Austin and G.E.M. Anscombe, were circulated in different coloured notebooks, eventually being published in 1958 as The Blue and Brown Books.

The British Foreign Office considered him loyal enough to be made a naturalised citizen in 1938, and he was made a professor in 1939, but he decided to spend the years of the war first as a hospital porter in London's Guy's Hospital, and then as a laboratory assistant in Newcastle Upon Tyne.

He was a professor at Cambridge from the end of the war until 1947, when he retired and moved to the Galway coast in Ireland to try and get his mature philosophy into publishable shape.

Working from the Blue and Brown books, he compiled many short aphorisms and philosophical sketches, but didn't succeed in creating anything he considered worth sending to the presses, and ceased to work on the project in 1949, when he was diagnosed with prostate cancer.

Returning to academic life in Vienna, Oxford and Cambridge, he continued philosophical work for another two years before succumbing to the disease on the 29th of April, 1951. His output from this period was posthumously published as On Certainty.

Two years after his death, in 1953, the material he had created, and all but abandoned, in Ireland was published as Philosophical Investigations, which many regard as one of the most significant philosophical works of the Twentieth Century. Arguments about its meaning and significance are still very much raging today, fifty years later. His last words were "Tell them I've had a wonderful life."


Sources:
http://www.utm.edu/research/iep/w/wittgens.htm
http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Wittgenstein.htm
http://www.cohums.ohio-state.edu/philo/people/salerno.7/bio56.htm
http://www.sbu.ac.uk/~stafflag/ludwigwittgenstein.html
and others collected at
http://home.earthlink.net/~bwcarver/ludwig/