In a heady, heated, no bolds-barrel report, newspaperman Clark Mollenhoff dissects one of Washington's most controversial trends: the withholding of so-called classified information from authorized investigatory committees. Concentrating his fire on the ""self serving declarations"" of the Truman administration and the ""executive privilege"" principle of both Eisenhower and Kennedy, Mollenhoff recreates such shockers from the recent past as political favoritism in the RFC, Internal Revenue and Justice Department; the Budget Bureau clam up during the Dixon-Yates uproar; the McClellan committee's difficulties in breaking the ""security cloak"" over East-West trade deals; the secret settlement of an anti-trust suit involving AT&T; Sherman Adams' agency-intercessions on behalf of bosom buddy Goldfine: a GAO audit uncovering a multi-million dollar bungling of an Air Force missile program; and corruption in foreign aid re Laos and profiteering, Peru and waste, all implicating the ICA and the Departments of Defense and State. It is the author's contention that a policy of secrecy, for the most part, does not safeguard anything and that arbitrary rulings of what should and should not be aired only invite cynicism and/or complacency, costly to the taxpayer and a dead weight on national morale. Sharpest scenes: some slightly jaundiced vignettes from a few Ike press conferences, plus ironies and Capitol capers during the Army-McCarthy tiff. Tough, topical, tops....With the Estes' case headlined in the Press today, this provides background with news value.