In this ambitious project, British curator and critic Turner presents what he calls an ""investigation'' of American art photography since World War II. Contributions from four critics and historians (including Lewis Baltz) explore the relevance of humanism in photography and the influence of the '50s publication of The Americans and the journal Aperture while providing an in-depth look at the '70s. The essays are opinionated and abrasive, often overlapping and sometimes contradicting each other, but the four different approaches give the book vitality. Of the 80 photographers represented here, almost half are products of the '70s; included are major and minor photographers such as Ansel Adams, Helen Levitt, Minor White, Gary Winogrand, Jerry Uelsmann, Robert Adams and William Eggleston, as well as iconoclasts Les Krims and Clarence John Laughlin. The one inexplicable omission is of the influential Walker Evans.