Lester Wunderman, the advertising executive credited with pioneering the hugely successful modern techniques of direct marketing, with sales pitches aimed at targeted prospective customers in their homes and geared to their interests or characteristics, died on Wednesday at his home in Manhattan. He was 98.

A spokeswoman for his agency, the Wunderman Group, confirmed the death on Monday.

The chairman emeritus and co-founder of what became the world’s largest direct-marketing ad agency, Mr. Wunderman never graduated from college, had no formal training in advertising and got into the mail-order business on a two-for-one offer: one salary split between him and his brother. It proved to be a big bargain for Madison Avenue.

Long before anyone had ever heard of internet sales or interactive communications, Mr. Wunderman was widely credited with coining the term “direct marketing.” For decades he championed an industry that sent personalized ads to preselected people for products and services that they might actually want to buy, as opposed to the scattershot approach of general advertising for the mass audiences of printed publications and broadcast media.

Using ZIP codes and research databases to identify likely customers, Wunderman teams reached them at home with mailings, promotional letters, phone calls, and newspaper and magazine inserts. Sales rose dramatically with his inducements: toll-free telephone numbers for ordering, postage-paid subscription cards, buy-one-get-one-free offers, “loyalty reward” programs for brand buyers who came back.