This book has the subtitle '14 Easy Duets for Flutes' - a little optimistic I feel, but interesting nonetheless. We are into the realm of new techniques here, ranging from sounds on the headjoint in Flute and the Dolphin ( the easiest) to alternative fingerings, singing and playing, and harmonics. Some of the duets are tricky enough even without any of this! Each one does have all the techniques fully explained though, and they would make very good reading practice for more a more advanced student. One for the teaching bag I think.