"In the most obvious sense, the Elements is a textbook. It proceeds from the simple to the complex. It is beautifully organized. It is very clear, succinct as a knife blade. And like every good textbook, it is incomprehensible. Euclidean geometry calls for a collaborative effort between the initiated and the unenlightened, the teacher droning, the student drowsing, until mastery of the material builds slowly in the warm space between droning and drowsing."
David Berlinski, Infinite Ascent: A Short History of Mathematics