From the very beginning of investigation of human reasoning, philosophers had identified -- along with deduction -- two other forms of reasoning which we now call abduction and induction. Whereas deduction has been widely studied over the years and is now fairly well understood, these two other forms of reasoning have, until now, eluded a similar level of understanding. This book presents a collection of papers addressing the issues of the relation between abduction and induction, as well as their possible integration. These issues are approached sometimes from a philosophical perspective, sometimes from a (purely) logical perspective, but also from the more task-oriented perspective of Artificial Intelligence. The first book to address explicitly the problem of understanding the relation and interaction between abduction and induction in the various fields of study where these two forms of reasoning appear, it should be relevant to a variety of students and researchers from these different areas of study, such as philosophers, logicians, and people working in Artificial Intelligence and Computer Science more generally.