'These 'Mechanical Exercises' strengthen the muscles, making them supple, yet decisive, and they help to obtain in less time a secure technique, as far as the fingers and embouchure. They are equally of great interest to improve the homogeneity of the sound, the legato, and the timbre of the instrument. After practicing book 1 of 'Mechanical Exercises' the young student will continue in this present work to become familiar with the use of accidentals and enharmonic tones, and he will form the important habit of remembering accidentals for the entire measure.' Jean-Marie Londeix
Difficulty level, roughly compared to ABRSM exam grades. 0 is beginner, 9 is advanced (beyond grade 8).