A titanic job, nothing less. What Andrew Chug has done in this book A Reconstruction of Cleitarchus (ISBN 9780955679025) is comparing the surviving texts from Curtius, Diodorus and Justin to filter out the original work these authors have used themselves to filter out what was written by Cleitarchus of Alexandria. To a lesser extent Chugg also includes Arrian, although this author mainly based his book on the texts left by Ptolemy, and the Metz Epitome. A very handy drawing with the links used by each and every author in antiquity is quite revealing.
Cleitarchus, son of Deinon wrote his account in the decades following Alexander’s death and most of the surviving ancient texts were more or less based upon his work, although not a single copy has come to us since they all were destroyed or discarded at some time or another.
Chugg manages to pinpoint which texts or phrases are used commonly by Curtius and Diodorus, with eventually an addition when Justin uses the same words. A Table overview accounting for the matches is very helpful. And so is the Table showing the first division of the Satrapies soon after Alexander’s death in Babylon listing each territory with the name of the appointed governor (satrap) as given by Diodorus, Justin, Curtius, Cleitarchus himself, as well as separately by Arrian, Dexippus and the Metz Epitome. Sounds all very technical but it becomes quite interesting when in the end we are able to read this part of Alexander’s history as it was presumably put down by Cleitarchus in the first place. A daring undertaking but a highly interesting one.
Most of Chugg's book is centered around Cleitarchus' Book 13, covering the period from July 324 BC to July 323 BC and beyond, i.e. the very last year of Alexander’s life. The subjects treated here are many: the Flight of Harpalus; the Exiles Decrees, the Mutiny at Opis; Death of Hephaistion; The Cosseans; Death in Babylon; Aftermath and Entombment. After a detailed comment and investigation of each chapter, one can read the full text as it may have been put down by Cleitarchus initially. A captivating story, especially since certain paragraphs have been put back in their original sequence ensuring the continuity of events.
The book ends again with a Table giving for each episode in Cleitarchus' terms the corresponding sources and references with additional comments in the last column. If after all that you still have questions, please do get in touch with Andrew Chugg in person.