A pair of active bishops is frequently adequate compensation for a pawn, or even the exchange, in a middlegame position. Steve Mayer, Bishop v Knight: The Verdict
The queenside majority, the outside passed pawn, the 'good' and 'bad' bishop, have become standard reference terms. Many players still commit the error of extrapolating these notions to the middlegame, where in most cases endgame principles are reversed. Mihai Șubă, Dynamic Chess Strategy
In general, positions characterised by an open centre favour White, and Black should not enter them light-heartedly. Dražen Marović, Dynamic Pawn Play In Chess
Universal systems can save a player a great deal of time and preparation. The main drawback is that a player restricts the range of positions and structures that he plays, which in turn can limit his development as a player. Steve Giddins, How To Build Your Chess Opening Repertoire
The centre is the most important part of the board. If a player has total control of this part of the board, he is often well on the way to victory. Simon Williams, Improve Your Attacking Chess
In positions of strategic manoeuvring, where time is not of significance, activating the worst-placed piece is often the most reliable way of improving your position as a whole. Alexei Kosikov, Positional Play
The French Defence-player must not be squeamish about getting a 'weak' e pawn; the main thing is to eliminate White's strong e pawn. Cecil Purdy, CJS Purdy's Fine Art Of Chess Annotation And Other Thoughts - Volume Three