The slide trombone is fundamentally different from other wind instruments.
There are no keys, valves, or anything like that, but the instrument offers us other things, such as a slide that can be used for glissandi, as well as a variety of alternative slide positions that can be used in conjunction with the techniques discussed in this book.

The topic is a specific articulation technique, namely lip slurs between harmonics.

Flexibilities should be used as a tool which enhances and enriche...