When Your Parent Drinks Too Much. By Eric Ryerson. Facts on File Publications. $12.95. Eric Ryerson is a pseudonym, but there is nothing pseudo about this volume, which is subtitled "A Book for Teenagers." It could easily save the life of your niece or nephew or the kid next door if you made it available to them, and if you are a problem drinker you might offer a silent prayer that somebody will give it to your youngster.

So-called self-help books are everywhere these days, and more and more are being offered to people with alcohol problems in their lives, either on the receiving end of a brandy snifter or in front of the fist of a surly, drunken spouse. There are big bucks in the treatment of alcoholism, and last semester's I'm-Okay-You're-All-Right genre is being touched up this term as "I'm Sober and You're Not" for the widening audience who need some relief from the onslaughts of John Barleycorn.

Most of these books are very narrow in scope, such as how to cope with being a former Roman Catholic Lithuanian single parent with a gin and bitters habit and an aging mother who smokes dope. This one is very straightforward, addressed to the 13- to 19-year-old who is puzzled by the erratic, apparently unloving and sometimes frightening behavior of one or more parents who can't keep the plug in the jug.

Whoever Eric Ryerson really is, he knows the territory, having been raised by an alcoholic mother and a nonalcoholic father who was as baffled by his wife's excessive drinking and subsequent behavior patterns as was his son, and who served as enabler, apologist and goat during the author's formative years.

Ryerson has written a warm and loving book, and he has written it with style and considerable talent. For instance, he writes to his teen audience: "You may also feel tense and afraid, never knowing what might happen next or what might trigger another disagreement or outburst. You're probably worried because nobody wants to talk about the drinking problem (silence is the watchword in most alcoholic families) and because you sense that nobody can do anything to make things better . . . Whatever your particular feelings, you can be sure that there are lots of others -- literally millions of us -- who have shared them. We understand what you're going through."

Ryerson has chapters telling what the disease of alcoholism is, advising on the "Three Cs" (You didn't Cause your parent's drinking problem, you can't Control it, and you can't Cure it, so you have to accept it and get on with your life), how to get help and whom to call in emergencies, what Al-Anon and Alateen are all about and how to deal with a parent who has decided to get sober in a treatment program that includes Alcoholics Anonymous.

In this regard, as in many others, Ryerson is a strict fundamentalist regarding abstinence as the basis for continuing sobriety. He also separates out some of the other narrow self-help disciplines, such as adult children of alcoholics, while acknowledging their existence and importance.

One of the more dramatic and vivid effects of reading this book is that, while it is aimed at the children of alcoholics, those who have suffered from the disease of alcoholism might very well find new insights into their own behavior during their drinking years.

In the chapter "Good Intentions, Bad Results," Ryerson sets up this situation:

"Let's say your alcoholic father has just awakened on Saturday afternoon after sleeping off a hard night's drinking. Suppose things were really bad; he barged into your room at 3 a.m. to tell you what a louse your mother is; he knocked over a lamp and smashed it to pieces; he exchanged harsh words with your mother all night long; and earlier he embarrassed you terribly by getting on the extension and speaking some drunken gibberish when you were on the phone with a friend . . . "

This is a good description of a situation that is not uncommon in alcoholic families, and Ryerson goes on to tell the younger reader how he might be dealing with this situation in terms of detachment and using the three Cs. But it also is guaranteed to give new dimensions to the recovering alcoholic parent's realization that his or her life had, in the words of the AA first step, in fact "become unmanageable."

Sometimes there's no sense trying to give a book like this to a teen-ager, because the motivation to read it must be there first. It might be best just to have it available in your house, sitting on the coffee table perhaps, so the young person can see it while visiting. A mild show of trying to conceal it from youthful eyes might be very effective, too.

All in all this is an important book, and money well spent if you are watching a valuable human being about to wash out as a teen-aged victim of somebody else's alcoholism. It is, he points out, a family disease.