During the course of his thirty-year career in Italy between the early 1470s and the first years of the sixteenth century, Tinctoris witnessed the printing of only two of his own theoretical works. His glossary of musical terms, the Terminorum musicae diffinitorium, has been convincingly shown to have issued from the Treviso press of the author's compatriot and contemporary Gerardus de Lisa, around 1495, although the work had clearly been compiled in manuscript form some twenty years previously. The Diffinitorium has, indeed, fared relatively well at the hands of modern scholarship, though one suspects that its generic significance as an early musical dictionary has occasionally clouded critical judgement on its actual content, and there still remain unanswered basic questions as to why, and for whom, the book was printed at all. By contrast, the other, fragmentary treatise of Tinctoris to be printed in his lifetime, De inuentione et usu musice – a work frankly more interesting by far than the Diffinitorium – has received surprisingly scant attention, and a reassessment of the place, date and circumstances of its publication is long overdue. In addition, it seems appropriate to take the opportunity of presenting here some new fragments of the treatise which have recently come to light in north-east France.