ABSTRACT
The life history is not conventional social science "data," although it has some of the features of that kind of fact, being an attempt to gather material useful in the formulation of general sociological theory. The sociologist who gathers a life history takes steps to ensure that it covers everything reader want to know, that no important fact or event is slighted, that what purports to be factual squares with other available evidence and that the subject's interpretations are honestly given. The image of the mosaic is useful in thinking about such a scientific enterprise. The scientific contribution of such a life history as The Jack-Roller can be assessed properly only by seeing it in relation to all the studies done under Park's direction, for it drew on and depended on all of them, just as all the later studies of that Golden Age of Chicago sociology depended, a little, on it.
