Katia Popov (P) is a professional violinist who performs regularly with the Los Angeles Chamber Orchestra and the Long Beach Symphony. She also contracts with various studios to record music for the motion picture industry. In 1993, none of P's twenty-six employers provide her with a place to practice. P's living room in her apartment served as her home office. The only furniture in the living room consisted of shelves with recording equipment, a small table, a bureau for storing sheet music, and a chair. P used this area to practice the violin and to make recordings, which she used for practice purposes and as demonstration tapes for orchestras. No one slept in the living room, and P's daughter was not allowed to play there. P spent four to five hours a day practicing in the living room. P claimed a home office deduction for the living room and deducted forty percent of their annual rent and twenty percent of their annual electricity bill. The Evil Empire (D) disallowed the expenses. The Tax Court concluded that P was not entitled to a home office deduction because her living room was not her 'principal place of business.' In the court's view, her principal places of business were the studios and concert halls where she recorded and performed because it was her performances in these places that earned her income.