While working for the BBC Robert Simpson gave an illustrated TV lecture on the last of Beethoven's three 'Rasumovsky' string quartets, Op.59. This talk was so well received that he was strongly pressed to write a complete study of Beethoven's Op.59, but he countered that he did not wish to write any more words about music; he had already done a great deal in that line. Instead, he wrote three quartets of his own (Nos 4, 5 and 6) that explore those incomparable Beethoven pieces. The present book shows how this later music analyses the process used by Beethoven, and by contrast how Beethoven's work can unravel secrets of Simpson's art. The results are enlightening both for the ordinary listener and for the scholar.