In 1999 an unidentified, hide-bound French-Algonquian language manuscript dictionary was discovered in the Jesuit archives in Quebec. The Native language was identified as Miami-Illinois, and subsequent historical and bibliotic research into the identity of the author revealed that the book was the work of the Jesuit missionary Pierre-Francois Pinet, arrived among the Marni -Illinois-speaking Wea at the site of present-day Chicago in 1696.1 Dialect-related evidence within the document,2 supported by our knowledge of the trajectory of Pinet's life, suggests that he continued to work on the dictionary until his death among Miarm-lllinois-speaking Kaskaskia on the riviere des Peres at present St. Louis in the summer of 1702. Three other people made occasional entries in Pinet's book. Two were identified by handwriting analysis: Gabriel Marest and Jean Mermet, Pinef s Jesuit missionary colleagues and contemporaries among the Miaminiinois-speaking nations.3 The third hand was unknown, and although a wide historical and graphological net was cast to determine he was, it failed to snare him. However, what made establishing the identity of this Jesuit scribe all the more compelling was the fact that he was also the unidentified scribe of the large, highly polished Mami-fllinois-French manuscript generally known as the Gravier dictionary, after Jacques Gravier, an important missionary-linguist among the Illinois and Miami.4 In 2006 I mentioned this problem to John Swenson, a retired Chicago attorney has written about early Illinois history. He wondered if the scribe might be Jacques Largillier, a French trader-turned-Jesuit brother had spent nearly forty years in the West in the late 1600s and early 1700s. The subsequent historical research and handwriting analysis that I undertook proved Swenson's hunch to be correct.5 Some are aware that Largillier played an important role in the early fur trade in the West as well as in the earliest French exploration of the Mississippi. A few realize he was instrumental in estabUshing the famous French town of Kaskaskia in the Illinois Country. Now we see that he also set down with quill and ink a treasure of invaluable linguistic and ethnographic data in the form of a native language dictionary. Although Jesuit archivists in Canada and Europe could not locate any letter or document written by Largillier, several good samples of his signature are found in legal documents at Quebec's national archives.6 (See Plate 1) Largillier signed his name in a simple, clear, natural and consistent fashion, without paraph or flair, and the distinctive characteristics of his signature alone easily suffice to identify him both as the heretofore unknown hand in Pinet's dictionary and the mystery scribe of the grand Miami-Illinois-French dictionary. In 1964 the Quebecois historian Raymond Douville published an authoritative study of Jacques Largillier's life which is important to the present study. Therein we find that Largillier, nicknamed Ie Castor (the Beaver) likely for his early fur trading successes, was born around 1644 in France, probably in Picardy in the northern part of the realm. He arrived in Canada around the age of twenty, probably with the French emigrants of 1664, and records show that he first tried his hand at being a colonist. However, by the spring of 1666 he had found the adventures of the fur trade more to his liking. Notarized trading contracts indicate his presence in the western Great Lakes in 1669, 1670, 1671, and 1672. In fact, in the year 1671 he was at Sault Ste. Marie for the famous ceremony presided over by Daumont de Saint-Lusson and attended by important regional Native leaders at which France declared itself owner of the West. Along with the very who's who of French traders of that era, Largillier signed the document that certified that claim.7 In that same year, Largillier began his career of assisting Jesuit missionaries, starting with Claude-Jean Allouez at Sault Ste. …