A thinking-skills course at Montana State University is described, along with recent issues concerning the potential effectiveness of such courses. Advantages and disadvantages of different designs for studying the effects of thinking-skills training are also considered. The focus of the course is: hypothesis formation and evaluation, problem solving, decision making, reasoning, and memory. The general approach is to briefly review cognitive research, especially that which concerns common pitfalls in thinking. Students are introduced to strategies to guide thinking, as well as to situations that illustrate the usefulness of different strategies. Practice in using the strategies is also provided. Short writing assignments are incorporated, since writing skills and thinking skills seem to be linked. In addition to subjective techniques for assessing thinking-skills courses, the following objective techniques are discussed: final examinations, performance in other courses, intelligence or critical-thinking tests, and Piagetian tasks. It is suggested that multivariate statistical techniques be used to explore changes in the underlying structure of cognitive skills and knowledge. (SW)