This study collects the papers presented at the Nonlinear Analysis and Optimization conference held at the Center for Operations Research and Econometrics (CORE) in Louvain-la-Neuve, Belgium. It was the firm belief of the organizers of the meeting that there is a natural interaction between the methods used in nonlinear analysis and the problems encountered in optimization, and that gathering the papers into one book would be beneficial for both parties concerned. The papers are mainly concerned with the following themes: nonlinear analysis, sensitivity (stability) analysis and algorithms in nonlinear programming (for smooth, nonsmooth and global problems).