Q: I need some suggestions for our baby's sleeping problem.

Our second child is nine months old. Due to lack of space he sleeps in the same large room as his 2 1/2-year-old sister. Very early on -- when he was four days old, in fact -- I developed the habit of picking him up every time he made a peep during the night, so he wouldn't wake her.

Over the nine months, he's had periods of a few weeks here and there where he has slept all night but most of the time he is up at least two and usually three or four times every night. I can't bear to let him cry it out, so I go to him.

I started the weaning process about a month ago, but still nurse him at night. His pediatrician feels he'll start sleeping when the process is complete.

He is above average for height and weight and naps for a total of about two hours a day.

A: You're not the only one with bedtime blues. Of all the queries this column receives, nighttime problems now score the highest.

While you want to end the nightly marathon, you still want your son to keep his sense of trust. Fathers solve this dilemma best.

Ask your husband to take over the night shift on a weekend, so he can sleep late at least for the first two mornings, and plan that it will end in a week. If you both stick to the program, it probably will.

Your husband's attention -- instead of yours -- should break the wake-up habit in about a week: A father with a cup of water isn't as much fun as another round of nursing. It also would defeat the weaning process if you let your son substitute nighttime feedings for daytime ones. This firm stand is not as heartless as it sounds. As long as his cries are answered and he gets his cuddles, he can get along without three or four extra meals at night.

It might be easier on the baby if you nurse him at his bedtime, and perhaps wake him for another nursing before you go to bed for the first few nights, so the weaning will be more gradual. If he cries during the night, however, it's your husband who goes to him and rocks him back to sleep, and he does this in the children's room. Your daughter soon will sleep through his squalls the way she does through traffic sounds and telephones.

You take over in the morning -- which may start as early as 5 o'clock, since he hasn't had those nighttime feedings -- but he soon should eat more in the day and sleep a little later.

As letters from other parents make clear, bedtime problems pop up at every age.

To the mother whose 2-year-old skips out of her big girl's bed, you should feel consoled by numbers. This is a classic age for this behavior. Most children want to be comforted then by their parents -- especially their mothers -- and they often want this comfort in the middle of the night.

They also sleep lighter then, perhaps because their molars come in, toilet training becomes an issue, or dreams get vivid and the fear of abandonment is big. Now you find that although you give your child lullabyes, stories and company until she falls asleep, before you know it, the midnight rambler is crawling into your bed again.

To many parents this is fine. They like the company and feel cozy. But for those whose child sleeps crosswise, flails, mumbles, and drags a few more possessions under your covers every night, the family bed can be a miserable place.

Tangible antifear devices should help then, and for years afterward. You can give your daughter a handkerchief under her pillow, touched with your perfume or her dad's after-shave (if she isn't an allergic child), or give her a flashlight, a music box, an old fur collar to wear or to stroke, a new and magical toy that keeps bad dreams away or a long ribbon between your bedpost and hers.

And for the first time she stays in her room all night, let there be a small, unexpected present from the sandman and occasionally gifts and notes from him when it happens again, but always given without promise, for that would be bribery.

Bribery doesn't keep these wanderers in their own beds, nor do spankings or threats -- all techniques tried by the mother of the 6-year-old who writes that her son has been afraid to stay in his own bed since he was hospitalized at 2. Now the problem is critical, since he has gotten too big for anyone's comfort.

Try instead a thin pallet or a sleeping bag on the floor in your room near your bed. This comforts a child but it isn't comfortable enough to keep the practice going. Different sleeping arrangements help too.

One idea is for you and your husband to move into his room after he's fallen asleep, leaving him in yours. This subtly tells him that his room is as safe as yours and after a week, you should be able to switch back.