Hal Evry, 79, a political consultant in the campaigns of California Gov. Goodwin J. Knight and Los Angeles Mayor Sam Yorty, among others, and author of the 1971 book "The Selling of a Candidate." Evry became known as an exponent of the view that a candidate should avoid controversial stands on the issues and run mainly under bland but positive slogans. Evry was born in Paducah, Ky., and educated at Columbia and Harvard universities, and pursued his consulting career in Los Angeles. On Sunday in Indian Wells, Calif., after a short illness.