The proposed work is to develop, implement and evaluate a temporal planning algorithm (called ZENO) which handles actions with conditional effects and universal quantification, real duration, continuous change, synergistic effects, domain axioms, and external events. In addition ZENO will reason about simultaneous actions which are potentially synergistic or interferent. The formal and empirical objectives are proving the algorithm is both sound and complete, yet finding methods that are efficient enough for practical use. To achieve these aims the techniques in the UCPOP planner will be extended with ideas from qualitative physics, operations research and constraint logic programming. In particular, a metric and temporal constraint satisfaction engine is envisioned based on the incremental Simplex algorithm.