The Dhatukatha (dhātukathā) is text from the the Abhidhamma Pitaka of the Pali Canon.
Translation: Discourse on Elements, tr U Narada, 1962, Pali Text Society, Bristol
This book combines ideas from the two preceding abhidhamma books, the Dhammasangani and Vibhanga. It is in the form of questions and answers, grouped into 14 chapters by form. Thus the first chapter asks of each item covered, "In how many aggregates, bases and elements is it included?" Later chapters progress to more complex questions like "From how many aggregates etc. are the dhammas dissociated from the dhammas associated with it dissociated?"