Sergei Ivanovich Taneyev was a Russian composer, pianist, teacher of composition, music theorist and author. Taneyev became the most trusted musician among Tchaikovsky's friends. The two developed a friendship that would last until Tchaikovsky's death. While Taneyev lacked an original creative gift, he was a fastidious and diligent craftsman with an unrivaled technique. Tchaikovsky realized that the opinions of such a man, whose own taste and competence were so high, yet whose self-scrutiny was so exacting, was to be respected. Therefore, Tchaikovsky came to greatly appreciate criticism from Taneyev. In fact, Taneyev became the only one of Tchaikovsky's friends encouraged by the composer to be absolutely frank about his works.