Ludwig Wittgenstein met Ben Richards, a medical student, in autumn 1945. It was the beginning of a deep and tempestuous relationship which lasted until Wittgenstein's death. Their correspondence starts in the summer of 1946 and consists of more than 370 letters, notes, telegrams and photographs. The final letter was sent a week before Wittgenstein died in April 1951.

Often defined by his arrogance, difficulty and critical nature of others, Wittgenstein writes letters to Richards which give us another window into his character. Their letters manifest an emotional closeness which is remarkable and unparalleled in Wittgenstein's voluminous correspondence. They leave no doubt that Ben Richards was Wittgenstein's closest friend in these last years of his life – indeed, perhaps the greatest love of his life.

Now available for the first time, the letters between Wittgenstein and Richards provide a wholly new perspective on the last years of Wittgenstein's life: his last years teaching in Cambridge, the resignation of his chair in Cambridge at the end of 1947, and the ensuing restless years spent trying to find a quiet place to do philosophy and complete his magnum opus, the Philosophical Investigations.

Their letters are further proof of the extent to which Wittgenstein's life was inseparable from his philosophy. They are an opportunity to come closer to understanding the work of this intellectual giant, telling us more about the values and beliefs of one of the 20th century's greatest thinkers.