This is an important volume, not only because Nicolaus himself witnessed crucial happenings at the court of Herod the Great and after the latter's death during his association with the Emperor Augustus, but also because T. has spent much of his scholarly life in Nicolaus’ company, and this new edition of Nicolaus’ Life of Augustus (Bios Kaisaros) and of his autobiography (Idios bios) is the splendid result. All parts are contained in the single volume, whereas F. Jacoby placed Nicolaus’ biographical works (F 125–30 [Kais.] and F 131–8 [IB], pp. 391–426) at the end of what remains of Nicolaus’ universal history, number 90 in IIA of Fragmente der griechischen Historiker, aligning him with authors who composed histories of the world now lost; Jacoby's commentary to the biographical works appeared in FGrHist IIC, 90, pp. 284–91. Jacoby online (BNJ) employs the same numbering as the print edition, but there commentary follows directly upon text.

Three chapters form T.’s introduction. The first chapter covers Nicolaus’ life subdivided into three periods: his early years up to 14 bc, the decade following when he served as philos to Herod, 14 to 4 bc, and Nicolaus’ later years in retirement, as friend and associate to Augustus, plausibly spent in Rome. The second chapter counters Jacoby's claim that the Bios Kaisaros was written in the mid-twenties and relied heavily on Augustus’ now-lost account of his own life in thirteen books, finished not long after 25 bc (Suet. Aug. 85.1) and narrating events prior to the end of Augustus’ Spanish campaigns against the Cantabri and Austures. Nicolaus’ first chapter implies a date for the Bios Kaisaros at a time when Augustus could boast he subdued those living on the west bank of the Rhine (ἡμερωσάμενος ὁπόσοι ἐντὸς Ῥήνου ποταμοῦ κατοικοῦσιν), so most likely in 12 bc or after ad 10 (ex. 1.1, pp. 68, 157–67). Throughout his commentary T. continues to note Nicolaus’ details that favour a date in the later years of the Princeps’ life. T.’s third introductory chapter examines the extant Bios Kaisaros and the fragmentary form in which it has come down to us as six discrete excerpts from the historical anthology commissioned by Constantine VII Porphyrogenitus in the tenth century: the first five excerpts are short and deal with Augustus’ upbringing and education from Constantine's section entitled Good and Bad Behavior (De virtutibus et vitiis) and preserved in a single manuscript from Tours copied in the eleventh century. Constantine's section entitled Plots against Rulers (De insidiis) narrates the assassination of Julius Caesar as preserved in the sixteenth-century manuscript housed in the monastery library of the Escorial. Although each manuscript brings its own difficulties, particularly troublesome are the misunderstandings of proper names from the late Republic, unfamiliar to Constantine's copyists (see pp. 177–9, on Atia, mother of young Caesar, after her marriage to her second husband L. Marcius Philippus, p. 62).

Jacoby (FGrHist IIA, 90, F 125–30 and F 131–8) was not T.’s only predecessor to work on Nicolaus’ biographical works, for there was K. Müller, FHG III 427–56, and then the contributors to the first edition of Excerpta historica iussu Imp. Constantini Porphyrogeniti confecta, T. Büttner-Wobst for De virtutibus et vitiis and C. de Boor for De insidiis. T.’s Greek text is for the most part close to Jacoby's, but disagreements with Jacoby regarding interpretation and contextualisation of the Greek are frequent. For example, Nicolaus’ narration of Caesar's return from Spain in 45 bc claims that young Caesar travelled back from Spain to Rome before his great-uncle did and that the main episode in that return was his encounter with pseudo-Marius (sect. 31–2). Plutarch's account of Caesar's return in that same year places both young Caesar and M. Antonius in the vanguard of Julius’ entourage, as the latter journeyed northward through Italy and Antonius received special honours (Plut. Ant. 11). Jacoby thought Nicolaus omitted Caesar's return because his source (Augustus’ autobiography) omitted it in the effort to avoid a positive picture of Antonius (FGrHist IIC, 90, p. 269). T., however, argues that Nicolaus probably did describe Caesar's triumphal procession in which many important Romans took part, perhaps even turning the story in young Caesar's favour (pp. 220–1), although the Constantinian excerpter eventually elided the story out. If the accounts of Plutarch and Nicolaus are combined, the complicated dashing back and forth required for young Caesar remains troubling. Nicolaus’ account of young Caesar during the earlier stages of his life shows him to be physically attractive, yet modest, obedient to his mother, precocious and more intelligent than others with whom he interacts. Nicolaus also tells us that young Caesar and M. Vipsanius Agrippa are about the same age, friends since they were teenagers at school (ex. 3, sect. 16). Young Caesar saved the life of an older brother of Agrippa, an early example of the former's willingness to intercede with his great-uncle on behalf of a friend (prostasia). T. plausibly suggests that Nicolaus may be thinking of the manner in which Xenophon portrayed the young Cyrus in his Cyropaedia.

The dramatic narrative (ex. 6, sect. 37–139) of the plot against Julius Caesar and its culmination in his murder during a meeting of the Senate in an anteroom of Pompey's Theatre (sect. 58–100) is preceded by a glance at young Caesar waiting in Apollonia and learning of the assassination from his mother's messenger; he eventually departs for Rome to assume the legacy left to him by Caesar, now known to all as his father through testamentary adoption. He is already keen to avenge the death (sect. 37–57). Nicolaus backtracks to narrate the story from a Roman viewpoint, and he presents vignettes that are familiar in later accounts as well, but sometimes told in a different order, such as the efforts to crown Caesar at the Lupercalia (sect. 71–5, pp. 301–15). Two details regarding Caesar's death – the number of conspirators (80 in sect. 59, pp. 98, 270–1, but about 60 in e.g. Suet. Iul. 80.4) and the number of stab wounds Caesar received (35 in sect. 90, pp. 118, 345, but 23 in e.g. Suet. Iul. 82.2) are at odds with the remainder of the tradition. It has become customary to assume Nicolaus inflated numbers when his inflation flattered young Caesar, as, for example, the lad's age when he spoke before a crowd at nine, or fourteen when he assumed the toga virilis, in both cases a year or two younger than in other sources (sect. 4 and 7, pp. 70–2, 176–7, 182). The higher figures for conspirators and stab wounds, however, may represent an alternate tradition available to Nicolaus, but apparently lost to us.

When compared to the Bios Kaisaros, Nicolaus’ autobiography occupies a mere seventeen pages of text and translation, plus five for the commentary; the first two excerpta are drawn from biographical material about Antipater, Nicolaus’ father, and of Nicolaus himself, both of which were subsumed into the Suda. Excerpta 3, 4, 5, 7 and 8 are from the Constantinian De virtutibus et vitiis, and the longest, ex. 6, from De insidiis, concerns the aftermath of Herod's illegal invasion of Arabia; Nicolaus’ success in reconciling Herod with Augustus; Nicolaus’ prosecution and conviction of Antipater, Herod's eldest son by his first wife; and Nicolaus’ management of the succession among Herod's three surviving sons, Archelous the ethnarch and his two younger brothers. Through personal experience Nicolaus learned the difference between being a ϕίλος to a Hellenistic monarch, often dangerous and exasperating, and an amicus to the Roman Augustus.