This text starts at the foundations of the field, and is accessible with some background in functional analysis. As such, the book is ideal for classroom of self study. The new material covered also makes this book a must read for researchers in the theory of critical points.

Critical Points of Functionals.- Minimax Systems.- Examples of Minimax Systems.- Ordinary Differential Equations.- The Method Using Flows.- Finding Linking Sets.- Sandwich Pairs.- Semilinear Problems.- Superlinear Problems.- Weak Linking.- Fu#x010D;#x00ED;k Spectrum: Resonance.- Rotationally Invariant Solutions.- Semilinear Wave Equations.- Type (II) Regions.- Weak Sandwich Pairs.- Multiple Solutions.- Second-Order Periodic Systems.