Igor Stravinsky was a Russian composer and conductor who is considered one of the most important composers of the 20th century. His music went through several distinct phases, including a period of neoclassicism and a period of serialism. Stravinsky's compositions include ballets, symphonies, operas, and chamber music. His most famous works include his ballets 'The Rite of Spring' and 'Petrushka,' as well as his 'Symphony of Psalms' and his opera 'The Rake's Progress.'