Non-linear and global optimization is a rapidly growing field of optimization dealing with theoretical, computational, and applied aspects of problems arising when people face the necessity to find optimal in some sense solutions. The importance of non-linear models continuously increases in our more and more complex world. As a consequence of this growing complexity very often objective functions are not only non-linear but also multiextremal, i.e., they can have several local optima and it is required to find the global one since the global solution can give a significant improvement with respect to the local ones.The core of this special issue consists of papers presented at the International Conference "Numerical Computations: Theory and Algorithms" held in Falerna, Italy in June 2013. The goal of the Conference was to create a multidisciplinary round table for an open discussion on numerical computations by using traditional and emerging computational paradigms. Numerical algorithms for solving non-linear and global optimization problems were among the main topics of the conference.Below we give a brief presentation of papers included in this special issue.• The paper [1] by Lucidi, Maurici, Paulon, Rinaldi, and Roma proposes a derivativefree approach for a simulation-based optimization problem in healthcare. Hospitals have been challenged in recent years to deliver high quality care with limited resources. Given the pressure to contain costs, developing procedures for optimal resource allocation becomes more and more critical in this context. The authors develop a simulation-based optimization approach for the resource planning of a specific hospital ward and report results or a real-world problem coming from B Yaroslav D. Sergeyev