Flexibility for the beginner by Yves Demarle (born in 1946) is helping Trombone beginners and intermediate beginners to master the legato. Published in 1981, Flexibility for the beginner can be used both by adults and children Yves Demarle is a French Trombone player who was soloist at the Paris Orchestra and who is currently teaching Trombone at the Regional Paris Conservatoire.