The Elzevirs printed Descartes' philosophical works in quarto format six times between 1644 and 1677, and the parts of each ed. were sold together and separately, in many different combinations; cf. Willems, 1008. The present configuration of texts consists of the first 3 works of the 1650 (2nd) ed.--the Principia, Specimina, and Passiones animae-- to which has been added the 1654 ed. of the Meditationes.