America is awash in a sea of drugs. Three billion prescriptions are written annually in this country. Almost one half of us take one or more drugs regularly. Fifteen million of us pop aspirin daily, 10 million take antihypertensives, another 10 million down a daily oral contraceptive, while 5 million don't make it to sundown without a tranquilizer. Drugs are a major industry, a major expense and a major hazard in the United States.

James Long, M.D. a veteran clinician and director of Health Services for the national Science Foundation has compiled a massive but readable volume detailing the ins and outs, the benefits and the risks of those medications commonly used in medical practice. Designed for the lay person, clearly organized, and carefully set forth. The Essential Guide to Prescription Drugs is subtitled "What You Need to Know for Safe Drugs Use" and would be a useful addition to the basic library of most households. The book starts from the premise that it is best for people about the medicines they are consuming. A busy physician and an anxious patient rarely exchange all the information they should about a new drug. Dr. Long's guide will pick up where the doctor patient relationship leaves off.

Missing from the volume are comments on drug prices and pricing, over-prescribing and patient pressure for medications. In fairness, one good pill can't be expected to do everything . (Harper & Row, $25)