Amazon.comThe Fifth Symphony shares some of its musical material with the opera The Pilgrim's Progress, and the composer dedicated it "without permission" to Sibelius. Indeed the work has something of Sibelius's nature poetry about it, as well as a solemn, almost religious quality in the slow movement. The Sixth, by contrast, is the composer's bleakest and most terrifying work, the second movement being a close relative of Holst's "Mars," from The Planets. There's actually quite a bit of "space" music in this score, not least in the finale, which is played entirely at the lowest possible dynamic level. Leonard Slatkin's performances are among the finest available. --David Hurwitz