No. 1: Josef Hofmann on Memorization
From: Piano Playing 1909 Doubleday, Page and Co.
Start with a short piece. Analyze the form and manner of its texture. Play the piece a number of times very exactly with the music before you. Then stop playing for several hours and try to trace the course of ideas mentally in the piece. Try to hear the piece inwardly. If you have retained some parts fill the misssing places by repeated reading of the piece, away from the piano. When next you go to the piano - after several hours, remember - try to play the piece. Should you still get stuck at a certain place take the sheet music, but play only tht place (several times if necessary), and then begin the piece over again as a test, if you have better luck this time with those elusive places.
If you still fail, resume your silent reading of the piece away from the piano. Under no circumstances skip the unsafe place for the time being and proceed with the rest of the piece. By such forcing of the memory you lose the logical development of your piece, tangle up your memory, and injure its receptivity.
Another observation in connection with memorizing may find a place here. When we study a piece we - unconsciously - associate in our mind a multitude of things with it which bear not the slightest relation upon it. By these things I mean not only the action of the piano, light or heavy as it may be, but also the colour of its wood, the colour of the wallpaper, the discoloration of the ivory on some keys of the piano, the pictures on the walls, the angle at which the piano stands to the architectural lines of the room, in short, all sorts of things. And we remain utterly unconscious of having associated them with the piece we are studying - until we try to play the well-learned piece in a different place - in the house of a friend or, if we are inexperienced t enough to commit such a blunder, in the concert hall.
Then we find that our memory fails us most unexpectedly, and we blame our memory for its unreliableness. But the fact is rather that our memory was only too good, too exact, for the absence of or difference from our acccustomed surroundings disturbed our too precise memory. Hence, to make absolutely sure of our memory we should try our piece in a number of different places before relying upon our memory; this will dissociate the wonted environment from the piece in our memory.

