  Computers are quickly gaining on us. Artificial systems are now exceeding the
performance of human experts in several domains. However, we do not yet have a
deep definition of expertise. This paper examines the nature of expertise and
presents an abstract knowledge-level and skill-level description of expertise.
A new level lying above the Knowledge Level, called the Expertise Level, is
introduced to describe the skills of an expert without having to worry about
details of the knowledge required. The Model of Expertise is introduced
combining the knowledge-level and expertise-level descriptions. Application of
the model to the fields of cognitive architectures and human cognitive
augmentation is demonstrated and several famous intelligent systems are
analyzed with the model.
