[3][4] The original work may not have been truly a selection of excerpts so much as an anthology of whole texts rearranged thematically.
According to the preface, the project involved taking the works of selected historians and rearranging their passages by topic rather than chronology so that "nothing contained in the texts would escape this distribution into subjects; by this division according to the content nothing of the continuous narration is omitted, but rather it is preserved entire.
[1] There is some material preserved in the surviving Excerpts that is not preserved anywhere else, including selections from Polybius, Nicolaus of Damascus, Dexippus, Eunapius, Priscus, Peter the Patrician, Menander Protector and John of Antioch.
[1][4] Other historians included were Thucydides, Xenophon, Diodorus of Sicily, Dionysius of Halicarnassus, Josephus, Arrian of Nicomedia, Iamblichus, Appian of Alexandria, Cassius Dio, Socrates of Constantinople, Theodoret of Cyrrhus, Sozomen, Philostorgius, Zosimus, Procopius, Agathias of Myrina, Theophylact Simocatta, John Malalas and Malchus of Philadelphia.
Two more original volumes survive in part: the Excerpta de virtutibus et vitiis (On virtues and vices) in the Codex Peirescianus and the Excerpta de sententiis (On gnomic statements) as a palimpsest in the Vatican Library (Graecus 73).