In the ‘70s, pianist Keith Jarrett made a big splash with his live solo albums. At the time, the former Charles Lloyd and Miles Davis sideman was also making a name for himself with his quartet, but the solo releases were groundbreaking. Jarrett dazzled listeners with his ability to improvise at length without anything planned out in advance; 1975’s The Koln Concert is probably the best known of these Herculean efforts. In recent years, he's returned to releasing solo material, but now the albums contain shorter pieces, and on Paris/London - Testament, which was recorded at concerts in Paris and London in late 2008, the pianist is in top form. The Paris concert opens with a lyrical passage that flirts with atonality; eventually the music turns thornier and more energetic. Other pieces from the show bring to mind Miles Davis, the blues, and even pop. The London concert opens with a meditative work, and the last track starts off as something that could pass for a hymn. But that latter cut turns into a rocker as Jarrett builds up a fiery, gospel-flavored groove.