The British composer John Stainer (1840–1901) was organist at St Paul's Cathedral from 1872 to 1888, and in 1889 became Professor of Music at Oxford. In this third edition of A Theory of Harmony he ceased to call it a theory founded on the tempered scale, as he had previously. He wrote in the Preface that he now believed the theory to be perfectly applicable to the system of just intonation. A further reason, in his view, was that the attitude of scientific men toward modern chromatic music had recently improved, as they could see that their system would never be adopted as long as it threatened the existence of a single masterpiece of musical literature. However, the system would be accepted when it rendered such works capable of more perfect performance. This influential Victorian textbook is now reissued for the benefit of those interested in nineteenth-century composition and analysis.