Exhibitions: Signals of Tomorrow

It was startling to see shocking-pink monuments, paintings of mountainous breasts and blinking assemblages inside and outside the ornate, Graustarkian palaces. Once again it was time for the staid city of Kassel-in West Germany to come to hypermodern life. It happens every four years. The occasion is Documenta, an international exhibit that on three previous occasions established a reputation as the most comprehensive survey of new art anywhere.

The present Documenta IV more than lives up to its reputation—a particular triumph in troubled '68. The near recession in West Germany last year...