In studies of author attribution, measurement of differential use of function words is the most common procedure, though lexical statistics are often used. Content analysis has seldom been employed. We compare the success of lexical statistics, content analysis, and function words in classifying the 12 disputedFederalist papers. Of course, Mosteller and Wallace (1964) have presented overwhelming evidence that all 12 were by James Madison rather than by Alexander Hamilton. Our purpose is not to challenge these attributions but rather to useThe Federalist as a test case. We found lexical statistics to be of no use in classifying the disputed papers. Using both classical canonical discriminant analysis and a neural-network approach, content analytic measures — the Harvard III Psychosociological Dictionary and semantic differential indices — were found to be successful at attributing most of the disputed papers to Madison. However, a function-word approach is more successful. We argue that content analysis can be useful in cases where the function-word approach does not yield compelling conclusions and, perhaps, in preliminary screening in cases where there are a large number of possible authors.