On Hanon
Most Pianists greatly overrate Hanon. (Strangely, sometimes more often students than teachers). These studies in the most mechanical type of "typewriter" keyboard technique; this sequence of incessantly monotonous patterns. Many keyboardists have been dealt physical harm from these petite agonies!
Robert Schumann was crippled using a cruel apparatus to "strengthen the ring finger", which is a destructive pursuit- actively denying a relaxed, flexible, and coordinated piano technique.
Of course, the general idea of fingerfertigkeit is useful in the performance of all piano music. Especially good texts and studies are:
Hummel - Theoretical-Practical Guide to Piano Playing - A Key to the Pyrotechnics of Beethoven & Mozart's Classical Virtuosity
CPE Bach - Essay on the True Art of Playing Keyboards - Immense artistic insight from the gifted son of Bach. Strategies for fingering in Baroque music, playing embellishments, interpretation, and improvisation in the Baroque/Classical style.
Clementi - Preludes & Exercises - Short studies in almost every key, with a culminating "Grand Scale" routine throughout all the Major & Minor Keys. Phenomenal preparation for Mozart, Haydn, and Beethoven
Liszt - Technical Exercises (10 Volumes) - The greatest text on the technique of Scales, Arpeggios, Chords, Chord-Scales, Octaves, Double Notes, Trills & Tremolando. Amazing Work. Unlocks the Romantic Virtuoso Technique in the Lisztian style.
Brahms - 51 Exercises - Further deepening of the Romantic approach to piano technique. Fascinating harmonic colors, poly-rhythms, and keyboard patterns with coordinating arm & finger movement.
That's a solid foundation to play Bach, Mozart, Beethoven, Chopin, Liszt, Schumann, Brahms, & Rachmaninoff (etc.....). This is advanced repertoire, there's a a lot of work in building to this. Start with Scales, Chords and Inversions, and Chord-Scales. The book Alfred's - Scales, Chords, Arpeggios & Cadences is a great primer. Then the above studies become more attainable.
Generally, I think these exercises are only useful in small doses. Otherwise you run the risk of making the majority of your practice session into a gymnastic workout, without any sustained musical content to challenge your mind and ear.
If you must play Hanon, there are a handful that have some value. I'd pick like 2 or 3 exercises at most, run them through the 12 major keys, and that's it. For my taste, I think the best ones are nos. 2, 3, 5, 6, 15, 20. Playing the first 20 continuously is a masochistic torture. The full 60 exercises is a death sentence.
Eventually you'll want to create your own patterns and sequences, and put these in various modes.
Here's a good primer on the 10 most essential modes to know in Jazz: https://www.coursera.org/learn/jazz-improvisation/lecture/9BClj/10-most-important-scales
If you put these in 12 keys, that's 120 scales, so plenty to work with! The mental and technical challenge of creating a melodic pattern and shifting through these modes a la Hanon, will benefit you much more than playing vanilla hanon from muscle memory.
Naturally, you'll also want to be studying harmony. How chords are constructed, inverted, extended, altered. How they are related to scales and how to harmonize melodies. This is the more important part of the art!
--K.S.