Memorization of variations could be even worse than playing in a tournament without looking in the books at all.
Mikhail BotvinnikI ... have two vocations: chess and engineering. If I played chess only, I believe that my success would not have been significantly greater. I can play chess well only when I have fully convalesced from chess and when the 'hunger for chess' once more awakens within me.
Mikhail BotvinnikChess is a part of culture and if a culture is declining then Chess too will decline
Mikhail BotvinnikWhen my opponent's clock is going I discuss general considerations in an internal dialogue with myself. When my own clock is going I analyse conctrete variations.
Mikhail Botvinnik