The OpenDT project was created in 2003 by Robert E. Banfield, and represents one of the very few free software packages for Machine Learning and Data Mining applications which are available for modification and redistribution. As the name would suggest, the current focus is on Decision Trees; more specifically, an ensemble of decision trees. Machine learning has benefited tremendously from the use of Multiple Classifier Systems, both in speed and in classification accuracy. An ensemble is one such type of multiple classifier system.