The Swiss mathematician Jakob Steiner (1796–1863) came from a poor background with an incomplete education, yet such was his mathematical talent that eventually the Prussian university system adapted itself to him rather than he to it. A geometer in an age dominated by analysts, he pursued his own interests in his own way. The elegant results which bear his name - including Steiner circles, systems and symmetrisation - are known to most mathematicians today. Considered by many to be the greatest geometer since Apollonius of Perga, Steiner did important work on systemising geometry, laying the foundation for much later work on projective geometry. Edited by the eminent mathematician Karl Weierstrass (1815–97), this two-volume edition of Steiner's collected works offers scholars access to his influential writings in the original German. Volume 1 was published in 1881.