The motivation for this chapter was to build on the previous work and continue to develop the utility of Neisser’s (1976) perceptual cycle model (PCM) as an explanatory tool for decision-making behaviour. There are two aims of the research. The first aim is to provide detailed descriptions of the three categories of the PCM in order to deliver a more complete understanding of the decision-making process. This is achieved in the development of the schema-action-world (SAW) taxonomy using data from 20 decision-making interviews. The second aim is to use this taxonomy to provide a detailed explanation of aeronautical critical decision-making (ACDM).