Bobby Jones, “The Art of Good Putting” (1933)

“The correct mental picture of the putting stroke itself is that of a sweep. I like to feel that instead of driving the ball toward the hole, I am merely sweeping it over the turf. The two essential factors in, and characteristics of, this kind of stroke are a marked flatness of the vertical arc on which the club head is swung, and a good alignment, which prevents cutting across the ball. As to the former, the head of the putter should never rise abruptly from the turf, either in going back or following through after impact.”
Click here for more info: Bobby Jones