The simple book of 40 Preludes are fun and deceptively amazing tools for working on blowing through groups of adjacent notes, which is a skill that directly applies to our everyday work in orchestral playing. They made their way back to my practice stand when I left both of my copies of Kopprasch across town in my locker at work. My go-to etudes are almost always Kopprasch; these Gallay gems seem to work their way to the bottom of the pile of etudes that I'm working on at any given time. Number 11 is my favorite.