Two letters. That’s all it is. Two letters, tongue on the roof of your mouth for the first one, purse your lips for the second letter. Ennnnn-ooooooo. Not gonna, ain’t happening, not a chance, uh-uh, thanks anyway, sorry-not-sorry, no.

So, as Linda Babcock, Brenda Peyser, Lise Vesterlund, and Laurie Weingart ask in their new book “The No Club,” why is that so hard for working women to say?

Left and right. Count ’em, you have two hands and at this moment, both of them are full – at work, home, everywhere. So why did you just say you’d be “happy to” take on another task, even though you’re clearly not?

That’s what a small group of women asked themselves and each other when they got together a few years back. Their lives and jobs were full but they still accepted more assignments without knowing why they did that. They set up what they called The No Club, and began to study this issue in earnest.

In every workplace, there are “non-promotable tasks,” or “NPTs,” as the authors call them. You can probably name some: taking notes for a group, serving on committees, training employees, picking up the slack left over by co-workers who drop the ball. These are tasks that aren’t often visible, are quickly forgotten or go unnoticed. They derail promotions and they can cause a loss of income. And women are saddled with these tasks because they’re asked to assume NPTs more often. But, say the authors, “Women aren’t the problem.

Organizational practices are.”

Saying “no” to NPTs begins by identifying them in an average workweek and by knowing what an NPT is and isn’t.

Next, recognize that managers and in-the-trenches workers both get dumped on when it comes to such tasks. Learn that there are several ways to say “no” to an NPT and the reasons why you’d say “yes.”

Then learn how to change your organization from the bottom up. Talk to management about “the promotability of work” and remember: “This is not a fix-the-women problem.”

Huh. There isn’t a book like this for men....

Take that as you wish. The fact that a book like “The No Club” even exists shows a need for women to read directions on how to say “no” at work.

But does it have to be so nice?

It’s a valid question that readers may ask. The authors show where female employees have gone wrong, where we need help and why, but there’s scant information on how to stand firm when you really, really can’t take on one more thing.

There’s advice on offering a gracious “no,” a different solution or a gentle reason for turning away a request. There’s kind advice on guilt and on starting your own No Club. But not a lot about serious, can’t-budge planting your feet, alas.

Is that a deal-breaker? Depends on how much you want your job.

Is “The No Club” a good start? Absolutely, because knowledge is power.

Should you miss this book?

MmmmmmNo.

Terri Schlichenmeyer’s reviews of business books are read in more than 260 publications in the U.S. and Canada.