The author's primary objective in this book is to discuss those aspects of bifurcation theory which are particularly meaningful to differential equations. To acccomplish this objective and to make the book accessible to a wider audience, much of the relevant background material from nonlinear functional analysis and the qualitative theory of differential equations is presented in detail. Two distinct aspects of bifurcation theory are discussed - static and dynamic. Static bifurcation theory is concerned with the changes that occur in the structure of the set of zeros of a function as parameters in the function are varied. Dynamic bifurcation theory is concerned with the changes that occur in the structure of the limit sets of solutions of differential equations as parameters in the vector field are varied. This second printing contains extensive corrections and revisions throughout the book.