"This book is a useful, enlightening, and thought-provoking exposition of the research and findings over the last 35 years of using and implementing variational techniques to better understand the dynamics of nonlinear field equations. These reviewers would highly recommend this text be on the shelf of any applied mathematician/physicist who uses variational techniques to analyze nonlinear field equations." (David J. Kaup and Thomas Keith Vogel, Mathematical Reviews, November, 2015)

• 1 The general principles.- 2 Solitary waves and solitons: abstract theory.- 3 The nonlinear Schrödinger equation.- 4 The nonlinear Klein-Gordon equation.- 5 The Nonlinear Klein-Gordon-Maxwell equations.- 6 The nonlinear Schrödinger-Maxwell equations.- 7 The nonlinear beam equation.- 8 Vortices.- 9 Appendix.

"This book is a useful, enlightening, and thought-provoking exposition of the research and findings over the last 35 years of using and implementing variational techniques to better understand the dynamics of nonlinear field equations. These reviewers would highly recommend this text be on the shelf of any applied mathematician/physicist who uses variational techniques to analyze nonlinear field equations." (David J. Kaup and Thomas Keith Vogel, Mathematical Reviews, November, 2015)

• 1 The general principles.- 2 Solitary waves and solitons: abstract theory.- 3 The nonlinear Schrödinger equation.- 4 The nonlinear Klein-Gordon equation.- 5 The Nonlinear Klein-Gordon-Maxwell equations.- 6 The nonlinear Schrödinger-Maxwell equations.- 7 The nonlinear beam equation.- 8 Vortices.- 9 Appendix.

"This book is a useful, enlightening, and thought-provoking exposition of the research and findings over the last 35 years of using and implementing variational techniques to better understand the dynamics of nonlinear field equations. These reviewers would highly recommend this text be on the shelf of any applied mathematician/physicist who uses variational techniques to analyze nonlinear field equations." (David J. Kaup and Thomas Keith Vogel, Mathematical Reviews, November, 2015)

• 1 The general principles.- 2 Solitary waves and solitons: abstract theory.- 3 The nonlinear Schrödinger equation.- 4 The nonlinear Klein-Gordon equation.- 5 The Nonlinear Klein-Gordon-Maxwell equations.- 6 The nonlinear Schrödinger-Maxwell equations.- 7 The nonlinear beam equation.- 8 Vortices.- 9 Appendix.