So you've made it through all the Schmitt, Hanon, Hertz, Cortot, Czerny, etc. exercise books. You feel confident about your abilities to play any 5-note phrase in any order and any key. Scales in 3rds, 6ths, and octaves? No problem. You doubt there are any piano exercises you COULDN'T do with aplomb and finesse.
My friend, it's time for these Liszt Technical Exercises to see what you're really made of.
These are not simple exercises. Oh sure, they start out simple, like they always do, but from there...let's just say you'd better have a pretty advanced technique to play these up to speed. As others have mentioned, dynamic markings make their presence felt, and you'd better know how to deal with them. But that's not really the crux of these exercises. They are made for advanced pianists with advanced technique, so unless you have it, I recommend going back to some easier exercise books (as mentioned above) and making sure you can play those at an advanced speed (108bpm tends to be the objective).
To sum up: this is the final book of piano exercises you'll ever need. Start with Schmitt and end here. In the meantime you'll have enough technique to tackle ANY existing piano piece. And when you finish, know that the only thing standing between you and concert piano stardom is YOU, because certainly you have the raw ability to play any piece you want.