The collected works of Thomas Aquinas are being edited in the Editio Leonina (established 1879). As of 2014, 39 out of a projected 50 volumes have been published.
The works of Aquinas can be grouped into six categories as follows:
In 1570 the first edition of Aquinas' opera omnia, the so-called editio Piana (from Pius V, the Dominican Pope who commissioned it), was produced at the studium of the Roman convent at Santa Maria sopra Minerva, the forerunner of the Pontifical University of Saint Thomas Aquinas, Angelicum. The critical edition of Aquinas' works is the ongoing edition commissioned by Pope Leo XIII (1882-1903), the so-called "leonine edition. Abbé Migne published an edition of the Summa Theologiae, in four volumes, as an appendix to his Patrologiae Cursus Completus. English editions: Joseph Rickaby (London, 1872), J. M. Ashley (London, 1888).