This article describes a taxonomy of problem-solving capabilities for wearable and context-aware computer applications. The authors developed this taxonomy from their iterative design methodology and experience with a wide variety of real end users, mainly mobile workers. They illustrate it using wearable systems whose capabilities range from basic stored information retrieval through synchronous or asynchronous team collaboration to context-aware platforms with a proactive assistant. Example evaluation methods illustrate how user tests can quantify wearable systems? effectiveness.