by Harold W. Stanley and Richard G. Niemi; Congressional Quarterly Press; 435 pages.

Franklin Roosevelt gave 998 press conferences during his twelve-year stint as President. That’s an average of 6.9 a month, which seems about right for a man who had to explain what he was doing about a national depression and a world war. In contrast, Richard Nixon gave only 37 during his nearly six troubled years in office, averaging one press conference every two months. What this statistic means, the editors of Vital Statistics leave up to the reader. That’s just as well, because interpreting the data in this book is half the fun of reading it.

Why, for instance, did the number of pages in the Federal Register , the executive branch’s daily publication of new regulations, jump from 35,586 in 1973 to 60,221 in 1975? Whereas the increase from 5,307 pages in 1940 to 15,508 in 1945 can be explained by the bureaucratic demands of World War II, was it Watergate or the oil crisis that caused a rise in the 1970s? Or, more realistically, was it the flurry of governmental regulations passed at the end of the Nixon era?

Vital Statistics provides the raw stuff of history. There are sections on standard subjects like the Constitution, elections, political parties, Congress, the Presidency and the executive branch, the judiciary, foreign policy, and economic policy; there are also data on topics like the popularity of public officials, media coverage of politics, and public opinion. You can find out that while Ronald Reagan had trouble with two of his nominations to the Supreme Court, John Tyler failed five times to get his man onto the bench and six times to secure three cabinet appointments between 1843 and 1844. You can look up the number of diplomatic posts the United States maintained in 1781 (4) and in 1988 (168). And you can determine which state has the longest constitution (Alabama) and which the shortest (Vermont).

All this is made plain. The charts can be read even by the functionally innumerate; sources are clearly stated at the end of each table. Included also are study questions that seem at first blush to be ridiculously simpleminded. They aren’t.