In the January 31 issue of PW, author, publisher and now bookseller Joan Drury made this memorable statement—about authors, publishers and booksellers—"We're all masochists, in our own ways."

I'd say "perverse" is an even better word.

For years, book people and the people who love—and cover—them decried the lack of widely available "hard numbers" about the sale of books. Publishers and some big agents could get point-of-sale information about their own books, of course; individual and chain booksellers kept store records; and bestseller lists provided some sense of context, but it was virtually impossible to find out how this or that title performed nationally over its lifetime.

So you'd think the appearance, a few years ago, of Nielsen BookScan would end arguments, clarify sales issues and please just about everyone. The service, which tracks point-of-sale purchases of books should, in theory, make life easier. Publishers, agents and authors would all be working from the same information about book sales, and could make more educated guesses about how and where to market the books they publish.

You'd think that—but you would, of course, be wrong.

(From the full disclosure department: Nielsen BookScan is owned by VNU, which publishes several publications competitive to PW. I've thought really, really hard about this and am quite sure that fact has not influenced my thinking about BookScan.)

Here's what some publishing executives have said recently about BookScan, which is believed to track about three-quarters of total sales of trade books:

"I love it. It provides a great indicator of how books are doing."

"It's a big wet blanket for publishing. It takes all the fun out of doing deals."

"I use it in negotiations with agents who are trying to oversell clients' past performances; the BookScan number is a reality check."

"I don't think BookScan is anywhere near accurate most of the time, and I hate when people throw around BookScan numbers as if they were gospel."

The last two comments, incidentally, came from the same editor.

It's certainly tempting to explain BookScan ambivalence by questioning the value of the numbers: the service doesn't track major sources like Wal-Mart or many religion bookstores, for example. Not to mention the fact that BookScan is so expensive (into seven figures for the full Monty) that, for many, questioning its worth is the only way to live with not affording it. But I think those explanations are only part of the story. The reason we don't fully embrace the closest thing we have to real information is far more psychological and emotional than numerical or financial. "This is a 'gut' business," one longtime executive told me. "Agents sell books they believe in; publishers need to love them to buy them. And while we're all in it, to some degree, for the money, blind love often takes precedence. That, and the fact that when you get into a heated auction, all you're thinking about is wresting the book away from the other guy."

Publishers aren't the first humans on earth to conflate love with money, and many an auction has been overtaken by a conviction that the more you pay for something the better it is. But when agents and editors truly fall in love with a book, there's a particular kind of blindness that descends. It's primal, almost, and magical, sort of—and not altogether a bad thing. Having BookScan step in like an overbearing parent who mentions that your beloved has had a couple of bad marriages and a questionable career path produces some of the same predictably resistant results. "Oh, Dad, take a walk. This time is different. I'll make it work. What do you know?"

BookScan does know some things, but not all, and while it clearly shouldn't be discounted, it also shouldn't be followed blindly.

Yes, the book business is just that—a business—and should be treated as such. But it's something more than that, too—an enterprise that requires renewals of passion, book after book, season after season. Oscar Wilde defined marriage as "the triumph of imagination over intelligence." But it was Samuel Johnson who offered the more pertinent wisdom for us: second marriage, he said, is "the triumph of hope over experience." In other words, love over data.