Required Reading: Classic resources you shouldn't research without.

Censuses are a staple of genealogical research. But researchers sometimes overlook state enumerations, a rich resource of data taken randomly and often in the 10 years between federal censuses. These head counts might ask different questions from their federal counterparts. The 1925 Iowa state census, for example, asked for parents' names — including the mother's maiden name — and their place of marriage. So how do you get these gems? State Census Records by Ann S. Lainhart (Genealogical Publishing Co.) is an indispensable guide, listing available censuses by state, then year The book's only draw-back: It hasn't been updated with details of online records and indexes. To find out what's available on the Web, type the year, state name and the word census into a search engine.