I'm sure many people here have heard of A. D. de Groot and his seminal study "Het denken van den schaker", later translated into English as "Thought and choice in chess". It was one of the first serious studies done into the thought processes of both master and amateur chess players, with many applications outside the chess world, as well. He is a very important figure in the history of psychology, and well known in Dutch pedagogic circles, as well. But never mind that: his original study is a truly fascinating view into the chess brain, and that's what important to us here.
Well, if you speak Dutch, you can now download the original thesis from
http://www.dbnl.org/tekst/groo004denk01_01/downloads.php
(In fact, if you don't speak Dutch, you can download it as well... but it won't do you much good.)
Richard