German conductor Wilhelm Furtwangler was legendary for his intensely felt and insightful interpretations, meticulously rehearsed and marked by a stubbornly unorthodox treatment of tempo. He did his most celebrated work between the world wars, for top-tier institutions like the Leipzig Gewandhaus Orchestra, the Berlin Philharmonic, and the Bayreuth Festival; his signature style famously transformed pieces by the big Bs (Bach, Beethoven, Brahms, Bruckner), as well as by Schumann, Wagner, and Richard Strauss. After the Nazis came to power, he continued to conduct for state-sponsored ensembles, provoking suspicions about his loyalties–suspicions that drove him into exile in Switzerland in 1945. (Within two years, however, he’d been cleared of pro-Nazi activity and resumed his directorship of the Berlin Philharmonic.) Furtwangler was also a respected composer, rare for a maestro of such stature. But his writing lacks the brilliance of his conducting, and after the creative ferment of Schoenberg and the Second Viennese School, he must’ve seemed like a throwback–many of his works clearly take inspiration from the lush chromaticism and narrative sweep of Romantics like Bruckner and Strauss. His finest material, most of which dates from the late 30s and 40s, is radiant and focused, given direction by the gradual resolution of a series of wildly disparate moods. Furtwangler completed the monumental Symphony no. 2 during his dark postwar days in Switzerland, and its agonizing swings between emotional extremes–terse and abrupt, gentle and elegiac, turbulent and frustrated–read almost like an autobiography. Daniel Barenboim and Chicago Symphony Orchestra administrator Henry Fogel number among the devotees who consider this symphony Furtwangler’s best work, and next week the CSO will give the piece its belated American premiere: Wednesday it’s paired with Mozart’s Piano Concerto no. 20, and for the subsequent concerts it shares a bill with Strauss’s Four Last Songs, which Furtwangler himself premiered in 1950. Barenboim is the soloist in the Mozart; the soprano for the Strauss is the superb Wagnerian Jane Eaglen. Wednesday, December 12, 7:30 PM, Thursday and Saturday, December 13 and 15, 8 PM, and Friday, December 14, 1:30 PM, Orchestra Hall, Symphony Center, 220 S. Michigan; 312-294-3000 or 800-223-7114.