Knowledge Discovery techniques seek to find new information about a domain. These techniques can either be manually performed by an expert, or automated using software algorithms (Machine Learning). However some domains (such as the field of lung function testing) contain volumes of data too vast for effective manual analysis, and require background knowledge too complex for Machine Learning algorithms. This study examines how the Multiple Classification Ripple-Down Rules (MCRDR) Knowledge Acquisition process can be adapted to develop a new Knowledge Discovery method, Exposed MCRDR. A prototype system was developed and tested in the domain of lung function. Preliminary results suggest that the EMCRDR method can be successfully applied to efficiently discover new knowledge in a complex domain. The study also reveals many potential areas of study and development for the MCRDR method, and Knowledge Acquisition and Knowledge Discovery methods in general.