No other books have been as helpful to me as the Mooney books.  I have and gone through all four multiple times.  The 170 Foundation Studies, and Dotzauer, and Grant are all great stuff, but Mooney targets the left hand very systematically and effectively, in a way that no one else has.

There seems to be a bit of a generational divide.  Younger teachers are much more likely to use Mooney than older ones.  But if a teacher rejects it, just work with it on your own as a supplement to the teacher's assignments.

And do work on the accompaniment parts, as well.  Mooney has put imagination and creativity into both the study pieces and the accompaniment parts.  For someone like me, who plays with others but has to make up his own parts, the accompaniment parts provide ideas and inspiration on how to do that for a wide variety of genres of music.

Now, a bit of explanation on the divide between the books.  The tunes in the Position Pieces Book 1 and 2 are maximized to help the student find the positions and to facilitate intonation.  They have no pre-existing tunes and the musical interest of the tunes themselves, especially in Book 1, is secondary to the goal of learning a position, or set of positions.

The Thumb Position books, on the other hand, contain mostly public domain folk tunes and Mooney's own compositions, and are less obviously pedalogical pieces.

Instrumental playing is based on multiple sensations.  One may hint at them, and induce them on occasion, but ultimately each individual must arrive at these sensations on his own.
Janos Starker