Ignorance is bliss, and a little knowledge is a dangerous thing. Consider Steven Brill, self-appointed watchdog of American journalism and founder of the magazine, Brill's Content, that modestly bears his name. Brill isn't truly ignorant about the journalistic craft of book reviewing, but on the evidence of a jeremiad in the current issue of his magazine, he knows just enough to have foolishly wrongheaded opinions about it.

Brill is on his high horse because, he writes: "Reviews of nonfiction books typically deal with almost everything about the book. . . . Everything, that is, except whether the book is true." He quotes two other self-appointed media watchdogs, Bill Kovach and Tom Rosenstiel, as drawing a distinction between the "journalism of assertion" and the "journalism of verification," and then hurls this thunderbolt: "Book reviews . . . have long been the province of the journalism of assertion."

He means as long ago as 1981, when the New York Times and the New York Review of Books made fools of themselves over "In the Belly of the Beast," an account of prison life by Jack Henry Abbott that reduced Norman Mailer, and others of the illuminati, to ecstasies of outrage and self-righteousness. More recently, Brill cites a review in the New York Times Book Review by Johanna Berkman of "Black and White on Wall Street," a book by Joseph Jett, a former Wall Street trader who left that occupation under what can charitably be described as a cloud of suspicion.

Discussing the Times's review of Abbott's book, Brill says, "I remember [the book] because Abbott had written the same garbage to me a year or two before in a long letter from prison, and I had checked it out and decided that its account of prison life couldn't be verified and sounded phony." If it strikes you that this claim--which is unverifiable except to the degree that one is willing to take Brill at his word--is a textbook example of the "journalism of assertion," well, that's how it strikes me, too.

As to the Times's review of Jett's book, and a similar one in Newsweek, Brill says that "any careful reading of the official record of Jett's case reveals him to be a liar who escaped prosecution for a variety of technical reasons," and that when he asked Berkman whether she had checked out the book's claims, she replied, "No, I got what I got from reading the book. . . . I typically expect that when a book is published that people don't lie." This provokes another Brillian thunderbolt:

"Of course, not every book reviewer, who typically writes a review for a few hundred dollars at most, can or should plow through the original source materials. . . . Nor can he or she re-interview people named in every work of nonfiction. But serious book reviews about serious books should try to do some or a lot of that. It's called reporting, and organizations like the Times and Newsweek have hundreds of reporters."

Brill doesn't have a clue. The issue isn't the money paid to the book reviewer but the amount of time available for Brenda Starr scooping such as he has in mind. If I may be pardoned for citing a personal example, in 35 years I have reviewed something on the order of 3,000 books. In the past decade most of these have been works of nonfiction. I have tried to bring to each an open mind and a skeptical eye, but there are limits--absolute, finite limits--to the "reportorial" scrutiny I could devote to any or all of them.

Take as a case in point "Morgan," Jean Strouse's biography of the financier, which was published in April. The book has 796 pages, of which 105 are bibliography and notes. I read the book with what I like to think was care, and made extensive notes on it before writing what was a highly favorable review. I did not check a single "fact" Strouse reported or a single "assertion" she made. Her facts struck me as just that--facts--and her assertions struck me as justified by those facts. It never crossed my mind that it was my responsibility to "report" this book, a process that had taken Strouse herself well over a decade.

Speaking only for myself, though doubtless this describes the approach taken by many others, in reading a work of nonfiction I look for the proverbial "ring of truth." Either a book sounds and feels right, or it doesn't. I try to stick to books in fields about which I know something and am always on the alert for minor, careless errors; a proliferation of these suggests that the entire project may be shoddy, and I warn the reader of the review about that. I like to think that years of experience give me some confidence and authority in this undertaking--just as Brill's years of experience in the law do the same for him when he writes about legal matters--but I cannot hope to be a book's editor, proofreader and legal counsel as well as its reviewer.

Errors get made, not just in books but in book reviews. In the front-page review in last week's issue of Book World, as all too many readers have been quick to point out, there were important errors that somehow were not detected by any of us on staff. Some errors are honest--nobody's perfect, not even, so far as I know, Steven Brill--and some are not. In reviewing a book, one does the best one can to ferret out errors of both kinds, but the hands of the clock turn on and on, and we have neither world enough, nor time.

Jonathan Yardley's e-mail address is yardley@twp.com.