Volume IV of SkrjabinÂ's Â"Complete Piano SonatasÂ" unites Sonata No. 9 op. 68 (nicknamed Â"Black MassÂ" Â- but not by Skrjabin) and Sonata No. 10 op. 70. These two works originated virtually at the same time, in 1911-13 and 1912-13, respectively. Christoph Flamm has given both sonatas a fundamentally fresh look in this new Urtext edition. Exploiting all the autograph sources, including SkrjabinÂ's sketches and drafts, he has arrived at surprising new readings. His foreword sheds informative light on the genesis and significance of these pieces; the many variants are documented in detail in the Critical Commentary. The high editorial standards are complemented by spacious engraving and practical page-turns.