From the Introduction: " Marston Morse was born in 1892, so that he was 33 years old when in 1925 his paper Relations between the critical points of a real-valued function of n independent variables appeared in the Transactions of the American Mathematical Society. Thus Morse grew to maturity just at the time when the subject of Analysis Situs was being shaped by such masters as Poincar , Veblen, L. E. J. Brouwer, G. D. Birkhoff,...