PASSSS: An Implementation of a Novel Diversity Strategy for Handling Constraints Abstract In this paper, we introduce PASSSS (PAS(4)), the Pareto Archived and dominance Selection with Shrinkable Search Space evolutionary computation algorithm. The main contribution of this paper is a diversity control mechanism embedded into the selection operator of an evolutionary algorithm that can be used (with little or no modification) to solve both single-objective and multi-objective optimization problems. We present a detailed description of the PAS(4) algorithm, and illustrate its capabilities by solving several engineering design problems and some test functions from a well-known benchmark in evolutionary optimization. Additionally, PAS(4) is also used to solve continuous and discrete multiobjective engineering optimization problems.