It began as a book about "the dark moments." The fatigue, the tug from two worlds and the constant nagging question in the back of the mind: Is it really okay to work and mother?

But authors JoAnn Miller and Gloria Norris made an unexpected discovery after interviewing more than 150 working mothers -- from hairdressers to stockbrokers -- around the country.

"Working mothers have far more up moments' than we realized," says Miller, 42, an editor, businesswoman and mother. "They are very successful, very resourceful and very enthusiastic. They are also very tired -- but, by and large, they are happy and fulfilled.

"Yes, they talked about doubts and guilts. But they also told us about the pleasure and sense of self they got from working and earning a paycheck. About real benefits that were flowing to their children, and how their husbands were sharing parenting in rewarding ways they never would have, had their wives been home full time."

The result of these interviews is "The Working Mother's Complete Handbook," (E. P. Dutton, 304 pages, $7.95) packed with tips on everything from how to get your husband and children to share the housework to what to say during a job interview.

The key, says Miller, to juggling diapers and memos, baby sitters and bosses is "relentless organization."

"Every Sunday night my husband and I sit down and plan our week. We list everything -- each meal, social plans, babysitters needed. We post it on the refrigerator so we know exactly how the week will go.

"You've also got to anticipate every imaginable problem. Have a list of alternate babysitters, hire a high-school student to entertain the children during school vacation and figure out different options for what to do if they're sick."

Whenever possible, Miller employs "time and aggravation savers" such as ordering by telephone, shopping for Christmas during summer vacation and allowing her 11-year-old to buy his own clothes.

But you can't try to do everything yourself, she warns. Those "macho mommies" who attempt to be enormously successful in their careers while running their homes single-handedly are sabotaging their lives.

In the home/job tug-of-war, the person a working mother often neglects is herself, adds Miller. "I find time for myself by combining things I like to do. I go to the gym with women friends so we can exercise and visit at the same time."

A self-described "working mother with a vengeance," Miller switched to a part-time editing job so she could start her own business as a publisher's agent.

"A mother can't always go straight to the top at an unbroken rate. Sometimes it pays to drop out for awhile to realign goals. You will still occasionally feel those jealous pangs of 'What-am-I-doing-with-my-life,' but the first requirement of pacing your career is a good dose of courage about not following the pack.

"Dropping out" allows a woman to enjoy motherhood, learn about herself, realign her goals and plans a career strategy, she says. Employers aren't suspicious of a woman who has five blank years on her resume. Some employers might see it as a favorable sign of her being settled.

"And having other strong commitments besides your job forces you to wrestle with your deeper needs and make choices that men and childless women aren't forced to confront until it's too late."