Although this catalog is, in more than one sense, a developmental history of American military insignia, it is not, and is not intended to be, a definitive study. The picture is far too incomplete. Whereas the record of Regular Army devices after 1821 is fairly clear--despite the fact that the uniform regulations continued sometimes to use the tantalizing phrase "according to pattern"--there remain serious gaps in the pre-1821 period when regulations were exceedingly vague and fragmentary at best; for example, the badges of the Regiment of Light Artillery (1812-1821). These gaps will be filled only by excavating at sites known to have been occupied by specific Regular units during particular periods. Indeed, since this study was begun, four unique and significant insignia were excavated at the site of a War of 1812 cantonment, and these greatly enrich our knowledge of the period. The record of insignia of the veritable multitude of independent uniformed Militia companies in existence during the period under consideration may never be complete. The selection presented here, however, is an excellent representative chronological cross section of typical designs and variations of insignia worn by the uniformed or "volunteer" Militia, as opposed to the "common" or "standing" Militia. The best sources of documentation and dating for Regular Army devices are the uniform regulations and ordnance regulations; these are supplemented by pertinent records in the National Archives, notably the letter files of the Purveyor of Public Supplies and of the Commissary General of Purchases. The letter files are voluminous, but in some cases badly mixed and in many cases incomplete. We have conjectured a reason for this incompleteness. The two prime contractors for military insignia during the period 1812-1821 were George Armitage and William Crumpton, both of whom had their small factories in Philadelphia within a mile of the office of Callendar Irvine, Commissary General of Purchases. The paucity of written transactions in the records in the National Archives between these gentlemen and Irvine tends to bear out our assumption that most of their dealings were conducted verbally in Irvine's office. This would account for the lack of sketches and drawings of cap plates and belt plates in files of the National Archives. In cases where no specific documentary evidence is available, dating has been based on a careful evaluation of design development and comparison with biographical specimens that can be more fairly dated through knowledge of the former owner's career. Excavated insignia from datable sites have also reduced the problem considerably.