The American ''middle class'' pays 75 percent of federal income taxes and produces most of the nation's goods and services. Its members are the families earning between $15,000 and $50,000 a year. The ''rich,'' families earning more than $50,000, make up only 3 percent of families in the US. The ''poor'' represent about 15 percent.
A number of first-rate books aimed at helping people manage their money were in print before this new one by Don and Joan German appeared. Three of the best are ''Everyone's Money Book,''(Dell, $8.95), by Jane Bryant Quinn; ''New Money Book For The '80s'' (Avon, $9.95), by Sylvia Porter; and ''Money Dynamics For the 1980s,'' (Reston Publishing Company, dist. by Prentice-Hall, $15) by Venita Van Caspel. All three are at least twice as long and detailed as the Germans' book; indeed they are almost encyclopedic.
So the Germans needed a gimmick to justify their book, and they targeted the middle class. Actually, the other books do too. Yet the Germans' book has some interesting ideas to offer and is more readable than the others.
The early chapters mix serious discussion with humor. (The Germans remind us, for instance, that Freudian psychologists attribute various money hang-ups to early toilet training). Beyond these chapters, the book offers plenty of good advice.
It's not get-rich schemes that the authors choose to discuss but planning based on the idea that one should never overrate money. Rather, it should be put it ''in its place.'' The middle class needs financial security for happiness, not riches, the Germans maintain.
''To improve your personal financial situation, there are only two things you can do,'' they write. ''One is to increase income. The other is to reduce expenses.''
After some 50 pages, the book gets into the more solid questions. There are, for example, chapters dealing with personal accounting; the merits of compound interest; how to choose financial advisers; dealing with a checking account; how to get a loan; making savings grow, cutting living costs; considerations in buying a house; the cost of bringing up children; shopping for life insurance; charitable giving; the economics of living together unmarried; bankruptcy; planning for retirement; and estate taxes.
The Germans are conservative. They advise that people should not borrow to make investments. They generally favor mutual funds over individual stocks. They are keen on such retirement schemes as individual retirement accounts and Keogh plans. They regard state lotteries as a bad buy. They lampoon some of the wilder investment letters.
Their explanations are easy to understand, and the book has a light touch (which occasionally seems strained). Overall, the book offers much sound financial advise. But if you want more comprehensive information, the older books are probably the better buy.