《示性类》内容简介：The text which follows is based mostly on lectures at PrincetonUniversity in 1957. The senior author wishes to apologize for the delayin publication.The theory of characteristic classes began in the year 1935 with almostsimultaneous work by HASSLER WHITNEY in the United States andEDUARD STIEFEL in Switzerland. StiefeI's thesis, written under thedirection of Heinz Hopf, introduced and studied certain "characteristic"homology classes determined by the tangent bundle of a smooth manifold.Whitney, then at Harvard University, treated the case of an arbitrary spherebundle. Somewhat later he invented the language of cohomology theory,hence the concept of a characteristic cohomology class, and proved thebasic product theorem.