This is a new annotated edition of Thomas J. Stieltjes' Collected Papers, first published in 1914 (Vol. I) and 1918 (Vol. II) by Noordhoff, Groningen, in French, and now published by Springer-Verlag, originally to mark the occasion of the 100th anniversary of Stieltjes' death (1894). These two volumes will be of great interest to all mathematicians who are anxious to understand the impact of Stieltjes' work on modern mathematics, and in particular...