Viktor Ullmann is mostly associated with the extraordinary flowering of music at the concentration camp at Terezín, where he was held from September 1942 until his deportation to Auschwitz in October 1944. Pianist Christophe Sirodeau argues that he should be approached "not as a victim of the Nazis, but on his own merits" but it remains difficult to dissociate his music from the circumstances of its composition. His seven piano sonatas explore themes of individuality, identity and tradition at times of extreme crisis. Ullmann's fondness for variation form allows him to link his own angry yet lyrical soundworld to those of Mozart, Mahler and Janá˘cek in Nos 1 to 4, composed in Prague as the Nazi threat loomed. Nos 5 to 7, written as a trilogy in Terezín in 1943, allude to other proscribed composers, such as Berg. No 7 closes with a gut-wrenching set of variations on a traditional Jewish folk tune. Sirodeau is an immensely persuasive interpreter. Recommended.