I seem to keep books all around and find myself reviewing certain books over and over.  I'm rereading CARLSON'S GUIDE TO LANDSCAPE PAINTING. Although I  wish all the pictures were in color,  Carlson is a master of words.  He makes me observe the landscape with a keener eye.  He says, "The sky is the key to the landscape."  I think that one thought is worth the whole book. One can get lost in painting trees and mountains and lakes   but  treat the sky as an afterthought.  I think there's a lesson there, too, that looking up clarifies one's surroundings.