The joint articles that we have written over the past twenty years fall into three different areas and consequently there is a natural division of this collection of our papers into three parts. Part I is concerned with our work in the foundations of probability, Part II with causality and quantum mechanics, and Part III with application of probabilistic models in education.

The five papers in Part I represent our joint efforts to clarify and extend the qualitative foundations of probability first given impetus in the important work of Bruno de Finetti. Both of us, but separately over a good many years, had extensive conversations with de Finetti about the foundations of probability, and several of our papers were inspired by questions he raised. In fact, the first two articles on necessary and sufficient conditions for existence of a strictly agreeing measure of a qualitative probability ordering were a response to de Finetti's early qualitative axioms and the subsequent search for necessary and sufficient axioms. The important point about our work is that in order to get simple axioms we had to go beyond the usual event structure of a probability space to elementary random variables. But we felt at the time, and continue to feel, that this is an extension that is very much in de Finetti's own line of thought, as reflected for example, in his introduction at an early stage of random quantities without an underlying probability space to represent them.