I begin with a brief piece of history: after studying in UCD, Pádraig Mac Coisdealbha went as a postgraduate to the Ruhr-Universität Bochum, where he researched for his doctorate under Professor Karl Horst Schmidt. He successfully completed this in 1974, with the dissertation entitled ‘The syntax of the sentence in Old Irish: selected studies from a descriptive, comparative and historical point of view’. On a visit to Ireland in 1976, he was killed in a car crash, aged 26. The dissertation was issued posthumously by the University in Bochum in a simple binding, under the direction of Professor Schmidt, and copies had been available in major Celtic library collections since then. In 1994, while I was conducting research into early Welsh syntax in Bonn, Professor Schmidt asked me to edit Mac Coisdealbha's work for full publication, taking account of the progress of research in the field in the meantime. After various delays, the book was finally published in 1998.