The sight of Richard Nixon, Spiro Agnew, G. Gordon Liddy and others capitalizing on their crimes through the selling of their books in prime time television would have delighted Samuel Johnson. Long ago, while enduring the writer's lonely struggle against poverty on London's Grubstreet, the great doctor gave the best advice to would-be scribblers. "No man but a blockhead ever wrote except for money," he pronounced grandly, thereby ending forever the foolish debate about the merits of publishing for profit or for the sensitive soul of the artist.

I say this as someone who has just completed a national book-selling tour via the electronic media.My crimes I leave to the critics to define. But the process of selling, whether involving such grand practitioners of the art as Nixon, Agnew, Liddy or less marketable ones, offers not only a commentary on American taste and changes in literary standards, but also it highlights the extraordinary impact television plays in all aspects of our lives.

Today, the way to reach readers of the printed page lies in the visual image that flits across a screen. Sam Johnson certainly would have been intrigued at that irony. "Why, sir, you can almost hear him fulminate, "that only proves what I have said before: Suce an excess of supidity is not in nature."

Phil Donahue represents the great literary success story in the age of television. He is, of course, the living example of a houshold word -- the electronics celebrity, the king of the world of talk -- whose very success on the air spawned success in other forms of expression.

His book, "Donahue: My Own Story," tells of his life as a TV talk show host. It instantly became a nationwide best seller, and the paperback rights are reported to have sold for $1.7 million.

Now authors of major reputations clamor to be on Donahue's show. The mere association with the talk king can lead, it seems, to their making the best-seller lists.

The struggle to get on such national TV shows can become fierce, for evidence strongly suggests that the exposure via the tube directly translates into sales. Knowledge that an author has been scheduled on one of these programs prompts the bookstores to order copies and display them. That decision itself is usually made far from the individual store -- most bookstores today are operated by national chains whose computerized selection of titles to be ordered and stocked for their commercial outlets are likely to be made from a medium-sized city such as Minneapolis. Again, TV exposure becomes a major consideration in whether a book even will be found in a store.

The process continues down to the local level. There, too, authors of renown vie to get on the local talk shows often for only the briefest of segments. Scarcely an author of standing exists who doesn't have some story -- whether of humor or horror -- to relate about certain of these appearances.

You stagger into a studio at virtually the break of day to find members of a zombie-like "live" audience waiting on rows of benches, their torpor broken only by the occasional bright flashing of the "Applause" sign soundlessly spelling out its message for them to clap or cheer . . . Or to encounter the TV interviewer who has not read a word of your book but is prepared to "wing it" with great authority and semblance of knowledge . . . Or who proves remarkably adept at ushering you out just before the arrival of the child clog-dancing team or the chef who prepares to demonstrate how to cook and carve a side of beef being wheeled before the cameras even as you exit.

If this seems somewhat demeaning, don't say so before the authors. They are aware of how important these appearances are to their livelihoods. Most are only too eager to go on the air as often as they can. In fact, they are the fortunate ones. Many talented writers never get a chance to give such exposure to their work. That, too, is a direct result of television, and its impact on publishing.

Several factors account for the rising influence of TV on how a book does.

One concerns the nature of book criticism. The day that a distinguished literary critic of national reputation and general audience -- an Edmund Wilson, John K. Hutchens, or John Mason Brown -- whose word could make a book appears to be passing. More and more critics come from the ranks of the specialists; they address a similarly small audience of other specialists in their fields. (My favorite example is of a critic appropriately named Karp who cheerily told me how a book of his died quickly after being savaged by an academic specialist in the pages of the same journal in which he was proceeding to carve me up.)

Television holds the mass audience, and it is to that general group that the publishers address themselves. They schedule major sums for national TV book tours, at the expense of print advertising. And they filter out those writers who are not as comfortable or effective in TV appearances. The author's prose may be superb, carefully crafted, brilliantly expressed, but if he or she happens to be shy or inarticulate in going before a mass TV audience the chances are they won't even be given the chance. They will be selected out in favor of those who project well over the tube -- or especially those who stir national controversy.

Not surprisingly, Nixon and Agnew come before us now only when they are hawking their new books. Dr. Johnson, the finest critic of them all, had a word for a situation such as this. In his customarily felicitous way, he said:

"It is a foolish thing well done."