Russian-born pianist Elena Bashkirova is talented enough to be a famous soloist in her own right, but in part because of her two marriages--to violinist Gidon Kremer and pianist Daniel Barenboim--she's still a relative unknown, overshadowed by her husbands' celebrity. Kremer was Bashkirova's spouse and constant collaborator in the 1970s, and during that time both her modernist tastes and her incisive style reflected his influence: she shared his zeal for Soviet avant-gardists such as Alfred Schnittke, and her playing, documented on chamber recordings they made together, was fiery, stringent, and intellectually probing. Bashkirova's relationship with Barenboim began in the early 80s, a decade before he became conductor of the Chicago Symphony Orchestra; after their two sons were born she cut down on her own performances, busy instead raising the children in a transatlantic household that often moved to follow the maestro. She has long enjoyed a reputation in Europe and Russia, both because of her pedigree (Bashkirova comes from a long line of distinguished pianists, and studied under her father at the Moscow Conservatory) and her appearances with Kremer, but it wasn't until the mid-90s that she came into her own in the States. Six years ago Bashkirova made her CSO debut in Mozart's Concerto for Three Pianos (alongside Radu Lupu and Barenboim), and in '98 she was back with the orchestra, performing Shostakovich's Concerto for Piano, Trumpet, and Strings at Ravinia. In recent years her repertoire has tilted toward the mainstream, dotted with Schubert, Schumann, and Beethoven, and her typically Russian ferocity and intelligence are now augmented by an evenhanded grace. She's scheduled to play Beethoven's Piano Concerto no. 4 at four upcoming concerts with the CSO, under the direction of visiting conductor Michael Gielen; the other half of the program is Beethoven's Symphony no. 3. And next Sunday she'll perform Schumann's Piano Quintet and Schnittke's Piano Quintet at Northwestern University's Winter Chamber Music Festival, which begins January 11 and runs weekends through the end of the month. With the CSO: Thursday through Saturday, January 17 through 19, 8 PM, and Tuesday, January 22, 7:30 PM, Orchestra Hall, Symphony Center, 220 S. Michigan; 312-294-3000. At the Chamber Music Festival: Sunday, January 20, 7:30 PM, Pick-Staiger Hall, 1977 South Campus Dr., Evanston; 847-491-5441 or 847-467-4000.