In the old days, before books were freely available, memory was paramount. As books become more widespread (after Gutenberg invented printing), methodologies for memorisation fell into disuse and were completely forgotten.
Consider Seneca who was mayor of Rome and knew all of its citizens by name. (In fact some politicians today have trained themselves to do the same feat). Or think about Pico de la Mirandola an Italian Renaissance intellectual who had a personal collection of some 30 000 books. You could go into his library, choose a book at random, give him the title of the book and a page number, and he would recite for you what was written in the page.
This seems completely amazing to us, but in fact it was quite common before 1500. In those days, if you went to University, you would learn five disciplines: Logic (or the art of correct reasoning), Oratory (or the art of public speech), Rhetoric (or the art of convincing intellectual adversaries) Mathematics (mostly geometry) and the art of memory. This kind of curriculum is all but forgotten, since nowadays we learn quite different things in University!
The art of memory concerned itself with creating on the student an artificial memory since it was understood that the normal memory we all possess is inadequate and insufficient.
The basic method was called “images and places”. Let us say you had to memorise a speech. Basically you would choose a public building and wander around it. Then as you entered a room, you would “hang” the first paragraph of your speech there, the second paragraph on the second room and so on. When it was time to recall the speech, you would then, mentally, go back to the building and retrace your steps room by room collecting the paragraphs of your speech.
This is the gist of the method. Because the art of memory was an University course taken for granted, many public buildings would be planned in such a way as to allow students of the art to use them as “places” to hang the “images”. So many characteristics of renaissance architecture can be easily explained as props for students of the art of memory (e.g. alcoves, columns, statues, etc.)
In our times, the art of memory has been slowly rediscovered, first by magicians and then by card players for whom a prodigious artificial memory can be a great business edge. (I think the record for cards shuffled and remembered is around 800. If they are not shuffled it goes to tens of thousands). There are two basic modern methods that do away with the need for buildings: the chain method (it allows you to remember anything in sequence) and the peg method, which uses numbers the way the old guys used buildings. The peg method allows you to remember things in any order.
This is really too large a subject for me to explain in detail here, so get a book of memory training. They all have more or less the same methods.
Try Harry Lorraine –“The memory book” for a start.
If you have the discipline to train yourself in the methods you will scare people with your super memory! (I should know, I do!). But be warned: it takes a lot of work until the process becomes subconscious.
For the history of the “Art of Memory” – a fascinating subject, the best reference is Frances Yates “The Art of Memory”. This is an academic book written by a historian. It is not really about tips to improve memory.
For piano applications, the only 2 books I came across are:
Walter Gieseking & Karl Leimer – Piano technique (Dover). Gieseking would only go to the piano after he had memorised the whole piece working solely on the score. This book explains this kind of mental practice with many examples. (But be warned, it is hard mental work!)
Lilias Mackinnon – “Music by heart” (Oxford University Press). This may be out of print. The psychological theory of memory is probably outdated (my edition is from 1944), but the tips and methods to memorise music are all usable.
Best wishes,
Bernhard