Folk Songs, written in 1964, has long been one of Berio's most popular works. A series of eleven songs for mezzo and chamber ensemble, it is couched in an accessible language with more than a hint of Stravinsky in the instrumentation. The songs here are not all folk songs: some are arrangements of popular songs in folk style and a couple are original Berio compositions, while the last song was transcribed from an old scratched 78 by the composer's then-wife Cathy Berberian. This performance, if occasionally a little scrappy, has an appealing rustic quality to it. However, Luisa Castellini, though she gives an attractive reading, doesn't have the sheer vocal beauty of Jard van Nes or the expressiveness of Berberian. Sequenza VI is the viola piece in Berio's extraordinary sequence of virtuoso solo pieces for fifteen different instruments. A frantic toccata in repeated notes and chords, it develops over eleven minutes in an increasingly diverse manner until it reaches an unexpectedly quiet conclusion. This is a veritable tour de force for the viola, and one the composer was later to base the concerto Chemins II upon. Sabrina Guiliani's performance is swifter and more restrained than Christophe Desjardins' on DG, but still highly effective. The disc ends with Pierre Boulez's 1984 miniature Dérevie for flute, clarinet, violin, cello, piano and vibraphone. This is a haunting six-minute piece that circles around the same musical monogram used in Les mots sont allés, garlanding it with delicate arabesques. This is late Boulez at his best, but the performance is nothing special, particularly when compared to the incisive, colourful reading with the composer conducting the Ensemble InterContemporain.