Q.I am quite perplexed when it comes to the idea of "firmness," "limit-setting" and "discipline" for pre-schoolers.

Well-meaning friends and older family members seem almost amused when I speak of my problems at home. My 3 1/2-year-old daughter, who is precocious, strong-willed and skillful, often gets the best of me. The environment is structured so that she can get into a minimum of mischief and my limits are stated clearly, but she tests them frequently.

I look her in the eye, tell her I'm angry about the behavior and let her know that it is not to be repeated. Later, I may give her a time-out, send her to her room with the timer, or deprive her of a special treat.

Many behaviors (getting into kitchen cabinets, coming out of her room at night, aggression toward other children, etc.) continue. People tell me, "I wouldn't let my kids get away with that," or "You've got to be in control so that she knows who is boss."

How does a parent go about being firm and consistent? Is it ever advisable to put a hook-latch on the outside of a child's door so you can enforce a 5-minute time-out without taking a child repeatedly back to her room? Are there other parents out there who don't understand what "firmness" is all about, or am I the only one? A.Parents and children have an extraordinary way of communicating with each other. Sometimes we think our actions speak as loudly as our words, but the children hear nothing. At other times, they read our underlying messages as if they were trained by Freud himself.

A loving parent can give a child lots of time on her weekends and a sackful of presents; take her to specialists and send her to classes; read her stories and help with homework; but unless she shows her respect and expresses her love explicitly, the child may never really believe she is loved.

And yet these same children never miss the truth when they are disciplined. When a parent is disappointed in a child's behavior, it's going to show, and when she's proud, that will show too. There's one thing you can depend upon: Unless a child is ill, she tries to act the way she thinks her parents want her to act, because they matter so much to her.

Unfortunately, a young child finds it easier to obey her impulses than her feelings.

A child's behavior reflects her age and stage, breaking apart before it can grow -- a basic law of nature. That's why she regresses in the second, third, fourth and fifth years -- usually around the middle -- and regroups around her birthday.

Even in the best of times, the best of children will be mischievous, for it will be years before the conscience is developed enough to make a child do what she should.

However, most children misbehave because they've been too obedient, reading the signals that parents didn't know they were sending -- and reading them right.

If there is a twinkle in your eye when your child disobeys or if she hears you describing her latest caper to your friends, you can bet that she'll repeat the performance. In a mixed message, the basic one is the one that's heard.

You also want to cut down on unnecessary orders, since most children usually get more of them than they can handle. To accomplish this, have no more rules than you're willing to enforce. If you won't see to it that your child picks up her toys or gets into bed, don't tell her to do it at all.

And when she doesn't obey, concentrate on correcting only one problem a week. A child usually ignores the scattershot approach.

You'll also want to remember that bribery, threats and rewards have their place, but it is a very small one, not just because you have to keep upping the ante but also because it divides the family into factions.

Time-outs are good, but not if the child is out of her room most of the time; nor is a hook-latch wise. This will only make her wonder whether you or the latch are in charge. It's far better to walk the child to a special corner, face her to the wall, hold her shoulders in place and say nothing at all, no matter how she carries on. Stay there only a minute or two, without saying how long.

After a few of these rounds, you can send her to the corner alone, but do this for an even shorter time, so you can end it in dignity before she tries to break free. When this discipline is successful, you can build slowly to a quiet five minutes in the corner so she learns to say no to herself.

In time you'll find that the raised brow and the level voice are the only corrections you need.

You also should remember that the rules you choose for your child to live by from ages 2 to 12 will have a profound effect from ages 12 to 20.

If you are very strict now, the child will go along now, only to challenge you when she becomes a teen-ager. If your rules are too free, however, she's likely to turn wild in adolescence. This leads to another paradox. Authoritarian parents eventually become permissive when they realize they don't have a choice, and permissive parents become authoritarian because they can't stand the situation anymore.

Practical parents walk the middle of the road, demanding as much obedience as they need for the family to be happy. And if you still have secret doubts about who's in charge, ask yourself: Who pays the mortgage?