This book follows on from a series of topographical monographs published by Filippo Coarelli on the Roman Forum (1983 and 1985), the Forum Boarium (1988), the Campus Martius (1997) and the Palatine (2012). In this volume, C. turns to the Quirinal and Viminal, the hills which extended north from the area of the Forum and Subura. The focus is on the Quirinal, with three long sections on topography and roads (1–81), cults (83–243) and housing (245–326). This portion of C.'s book is indebted to his multiple entries on the Quirinal for the Lexicon Topographicum Urbis Romae (ed. E. M. Steinby, 6 vols, 1993–2000). The last section deals with the topography, cults and housing of the Viminal (327–71). In Latin the hills were called the Collis Viminalis and Collis Quirinalis, the latter incorporating the Collis Salutaris, Collis Mucialis and Collis Latiaris. Only in this part of Rome were the hills known as colles, not montes, hence the title of the book.

The topography of the Quirinal and Viminal consists of a series of puzzles, and for C. one of the most important problems, discussed first and at length, is the location of the temple of Quirinus (83–112). Festus (303L) attests that the cult site of Quirinus was near the Porta Quirinalis, and most scholars place the temple south of the gate in the gardens of the Palazzo del Quirinale. C.'s objection is that this places the temple on the Collis Salutaris, hence he argues for a position north of the gate. In particular, he proposes that it stood on the site of the Palazzo Barberini on a large terraced platform which extended beyond the Servian Wall and the crest of the Quirinal. Only one section of a retaining wall survives, near the Via Barberini, and the premise for linking these remains with the temple of Quirinus is C.'s speculation that the Palazzo Barberini, not the Palazzo del Quirinale, was the findspot of a dedicatory inscription to Quirinus (CIL VI 565) discovered ‘in the papal gardens on the Quirinal’ during the papacy of the Barberini pope Urban VIII (93–6). C. illustrates his hypothesis with a ground plan which shows a large temple and a three-sided portico set on a terrace measuring 150 by 150 m (fig. 21). It is interesting and imaginative, but it is no less speculative than Carandini's plans of the temple and portico, set in the gardens of the Palazzo del Quirinale, which C. subjects to exhaustive criticism (87–92, with figs 16–17, reproduced from A. Carandini, Cercando Quirino (2007) and Atlante di Roma antica (2012)). It is known that the temple of Quirinus was a dipteral, octastyle temple (Vitr., De arch. 3.2.7) with seventy-six columns (Cass. Dio 54.19.4) surrounded by a portico (Mart. 11.1.9). Its exact location is unknown, however, so it cannot be shown as a ground plan on a map. C. examines a further eighteen cults on the Quirinal (112–243) and four on the Viminal (333–8), most of which are known only from brief references in the literary sources. C. is always erudite in his analysis, but for this reviewer he does not sufficiently acknowledge what is not — and cannot be — known. In the case of the temple of Quirinus, scholars have suggested that it stood in the gardens of the Palazzo del Quirinale (α) or north of the Via delle Quattro Fontane (β), while C. opts for the site of the Palazzo Barberini (γ). C. argues that γ must be correct because α and β are wrong, but these are not the only options, for there is also the possibility that the temple stood at an unknown location (δ) which cannot be identified on the map. C. ignores δ and pretends that the only options are α, β and γ. In short, he offers an argument based on a false dilemma.

This book examines cults, houses and other problems of topography, but it does not offer a complete survey of the history and archaeology of the two hills. There is extensive discussion of Imperial period houses attested for the most part only on the basis of inscribed lead pipes (312–26) but only passing reference, for example, to the third-century Mithraeum discovered in the grounds of the Palazzo Barberini (318, cf. 98). Several late antique houses are catalogued (312–26, nos 2, 23, 25, 48, 53, 66), but the Baths of Constantine receive no separate treatment, and there is also no systematic discussion of the most impressive building in this part of Rome, the Baths of Diocletian.