This book summarizes and develops further in some respects the results of research the authors have undertaken in the past several years on the problem of explaining probabilistic correlations in terms of (Reichenbachian) Common Causes. The results have been published by the authors of this book in a number of papers, partly in collaborations with each other and with other colleagues; these papers form the basis of the present book. We wish to thank especially Balázs Gyenis, Zalán Gyenis, Inaki San Pedro, Stephen J. Summers, and Péter Vecsernyés for the cooperation on the topic of the book and in particular for allowing us to use material in joint publications.

In our work we also have benefited greatly from collaborations and informal discussions with a number of other colleagues. These include Nuel Belnap, Arthur Fine, Jeremy Butterfield, Rob Clifton, Gerd Grasshoff, David Malament, Tomasz Placek, Samuel Portman, Elliott Sober, Leszek Wronski, and Adrien Wüthrich – we thank them all for their interest in our work and for their readiness to share with us their insights and views.

The research that the book is based on was partially supported by several small grants from the Hungarian National Science Found (OTKA). The final writing was facilitated by the OTKA grant with contract number K100715.