List of IllustrationsList of TablesAcknowledgmentsIntroduction: Machinists' TracesPart I: The Formation of the Networks, 1790-18201. Iron Foundries Become Early Hubs of Machinist Networks2. A Networked Community Built by Cotton Textile Machinists3. The Federal Armories and Private Firearms Firms Operate in Open NetworksPart II: The Elaboration of the Networks, 1820-18604. Iron Foundries Rule the Heavy Capital Equipment Industry5. Networked Machinists Build Locomotives6. Resilient Cotton Textile Machinist Networks7. The Cradles of the Metalworking Machinery Industry8. Machine Tool Networks9. Machinists' Networks Forge the Pivotal Producer Durables IndustryAbbreviationsNotesEssay on SourcesIndex