It is not widely known that the popular composer Petr Ilyich Tchaikovsky was also a music critic, nor that he was professor of musical theory and harmony, instrumentation and free composition at the Moscow Conservatoire (1866-1878). His teaching there bore fruit in the form of the 'Manual for the practical mastering of harmony' printed in Moscow in 1872. This textbook played an important part in Russian musical training: it was written before the manuals by Rimsky-Korsakoff and Arensky and is t...