The H.L. Clarke Technical Studies Book Expanded into the 21st century range.

In the old versions the etudes were in one key. The top note was too high for younger players and not high enough to work on range for experienced players.
This was a problem and it bothered me when I was in Middle School (too high) and in High School and College (not high enough).

I decided to fix that problem. I took the 1912 version of the book and I wrote the studies and Etudes in different keys and covering the range from Low F# to Double C.
If you are working on making high E, F, (whatever) a more stable note; this book has exercises that use that note.