A general paradigm for solving resource allocation, time-tabling and scheduling problems is presented. The paradigm is based on an expert system approach which looks for a feasible solution that satisfies the problem's real-life constraints, rather than on an analytic approach which looks for an optimal solution by using simplified constraints. The main feature of the new paradigm is a general control strategy which includes three parts that deal with allocation, with constraints checking and with changes to allocations, termed local changes. The proposed paradigm has been tested on several real world problems such as: crews assignment to air force missions and class scheduling for a university department. These problems were solved well in few minutes of run time by Prolog-based systems that implemented the proposed paradigm. The case studies are described in the paper, an overall evaluation of the methodology is given, and an outline of the Expert System Shell is presented.