 From these sources, scholars have attempted to piece together a picture of the content, and in some cases, the development of Stoic doctrine. In some areas, there is a fair bit of consensus about what the Stoics thought and we can even attach names to some particular innovations. However, in other areas the proper interpretation of our meagre evidence is hotly contested. Until recently, non-specialists have been largely excluded from the debate because many important sources were not translated into modern languages. Fragments of Stoic works and testimonia in their original Greek and Latin were collected into a three-volume set in 1903–5 by H. von Arnim, Stoicorum Veterum Fragmenta. In writings on the ‘old’ Stoics, fragments and testimonia are often referred to by von Arnim’s volume numbers and text numeration; e.g. SVF I.345=Diogenes Laertius, Lives 4.40. In 1987, A. A. Long and David Sedley brought out The Hellenistic Philosophers (LS) which contains in its first volume English translations and commentary of many important texts on Stoics, Epicureans and Skeptics. In 1988 Long and Sedley was followed by a collection of primary texts edited by B. Inwood and L. P. Gerson entitled Hellenistic Philosophy. Unless otherwise specifically noted, I refer in what follows to texts by or about Stoics using the author’s name followed by Long and Sedley’s notation for the text. For example, ‘Aetius, 26A’ refers to section 26 of Aetius’s work, text A (unless otherwise noted, I use their translation, sometimes slightly altered). The Inwood and Gerson collection translates many of the same texts, but unlike LS does not chop them up into smaller bits classified by topic. Each approach has its merits, but the LS collection better serves the needs of an encyclopedia entry. For French translation of Chrysippus, see Dufour (2004). For German translation of the early Stoa, see Nickel (2009).