This encyclopedia appeared first as a published volume in 2004, but the published and electronic versions evolved together, part of an integrated vision of a new kind of historical encyclopedia. It includes thousands of entries, historical sources, and special features. One special feature, a map of labor unrest in Chicago in April – May 1886, complements the two online projects related to the Haymarket affair just described. This interactive map, with a variety of tools for the user complemented by interpretive essays that draw on the Web’s hypertext capabilities, provides a rich context for understanding the more publicized Haymarket protest and bombing. (Dublin 2010: 92)