Recent advances in nonlinear differential equations are shown in 20 survey and original research papers, presented at the "Workshop on Nonlinear Analysis and Applications", held in Bergamo, Italy, July 9-13, 2001. This workshop was the third edition of the meetings which took place in Campinas in 1996 and 1998, illustrating the fruitful cooperation between researchers in Italy and Brazil. Many new theoretical results addressing elliptic partial differential equations, Hamilton-Jacobi, and Schrodinger equations, and analyses of various models are included. The book is Volume 54 of the Series Progress in Nonlinear Differential Equations and Their Applications.