Overall public investments in preschool in Iowa exceed $130 million annually, but there is no single information source that can answer the straightforward question, "Who participates in publicly financed preschool?" This is true for Iowa students as a whole, and for students grouped by family income, race and ethnicity, language, geography and special education status. By drawing on different data sources, however, it is clear that preschool is not available on a universal basis. Some populations--particularly those most likely to have subsequent challenges in school--participate at much lower rates than the population as a whole. (author abstract)