The problems associated with developing real-time software systems, including ensuring predictable real-time behavior under both normal and abnormal operating conditions, are outlined. The management of temporal complexity, structuring of dynamic real-time applications, object-oriented models, object-oriented real-time languages, and the requirements for real-time object-oriented models are discussed. Chaos, an object-based language and programming/execution paradigm designed for dynamic real-time applications, is described.<>