The work of Jean Mawhin covers different aspects of the theory of differential equations and nonlinear analysis. On the occasion of his sixtieth birthday, a group of mathematicians gathered in Sevilla, Spain, in April 2003 to honor his mathematical achievements as well as his unique personality.This book provides an extraordinary view of a number of ground-breaking ideas and methods in nonlinear analysis and differential equations.List of Contributors: H Amann, M Delgado, J L Gámez, A M Krasnoselskij, E Liz, J Mawhin, P Quittner, B P Rynne, L Sanchez, K Schmitt, J R Ward, F Zanolin, and others.