One of those few is Jeremy Silman. Though he has never been anywhere near FIDE's top 20, IM Silman has quietly become perhaps the best American writer of general instructive books aimed at the great mass of players in the middle area of the bell curve. Your Chess is an outstanding work. For anyone below that level, The Amateur's Mind may be a latter-day Book of Revelation, or at least a set of minor epiphanies that can add up to major chess improvement. The book is derived from Silman's regular column in Chess Life magazine.
Lessons fall generally into two parts.
The first is the illustration of a particular strategic theme or tactical technique from an exemplary game. Silman excels at finding or composing examples appropriate to his chosen themes, and explaining the principles they illustrate. Here Steinitz shows us that if you take away all their advanced squares, the horses become rather sickly creatures. Making the Knight move away from the fine post on d4. Defending the very important c5-pawn.