The futures that individuals have projected for cities have been frequently commented on and explored by scholars. London and Paris have particularly been expounded on and so it is welcome that these well-trodden paths get a new look from Carlos López Galviz. The old contention that the transport networks of London and Paris were respectively unplanned and planned are challenged through Galviz's extensive interrogation of a plethora of railway plans, maps and proposals. Ambitious in its objective, the work explores how different constituencies and actors in the two capital cities proposed, debated and ultimately had their ideas frustrated and transmuted (sometimes dramatically) between the 1830s and World War I. The work's central benefit is that alongside tracing urban development and the role railways played in this, it illuminates how what was not built is just as important as analysing what was; they are two sides of the same coin. Galviz considers that these processes were driven forward by three fundamental ideas.

The three central chapters of the book illuminate the nature of the debates over the cities’ futures and how transport systems have difficult births, connected with their immediate pasts, as well as what was happening at the time. The first chapter, entitled ‘Circulation and improvement’, emphasizes that before 1850 different organizations and individuals envisioned the railway improving the movement of passengers and goods around ever more congested cities. Dreams were not always realized, while plans did not always meet expectations. As Galviz concludes, ‘to improve was to circulate; but to circulate, on the streets and beneath them, need not always mean to improve’ (p. 97). The second chapter explores the tension between two ideas that permeated debates in both cities about the nature of railway construction: were lines to circumvent the city around the periphery, or serve the growth of suburbia and centrifugal forces? The cities took divergent paths. In London, the lines of the Metropolitan and Metropolitan District circumvented the centre, an extension of the main line railways to connect termini to create an open system linked to national systems. By contrast, in Paris, the system of an inner circle and lines crossing the city was separate from the main lines, reflecting the local desire to shape the city's growth rather than to connect to the beyond. In the final section, technology and specifically electricity comes to the fore, as well as the capitalist forces that drove it forward and that stimulated pioneers to electrify transport flows. In London, enterprising individuals, such as Yerkes, drove forward the idea of a cohesive network, yet this was not obtained, in consequence of there being established connections to lines that connected beyond the city. Parisians, however, remained served by an electric system that was bounded within the walls, but which provided an efficient, cohesive transport network.

This structure of the book provides the reader with unique insight into how the development of transport networks proceeded, attempting a comparison between the two cities’ paths. Ultimately, it stresses the fact London's underground (or to be more precise sub-surface) railways were designed to be connected with the national network, while in Paris this development was constrained by the city limits, a contrast to visions expressed through its wide roads and boulevards, and thus what developed there was a self-contained system. With such a wide range of scope, Galviz must be commended for the ambition in this work. Nonetheless, the book suffers from weaknesses that regrettably diminish its impact. Exploring the different plans and ideas that permeated the visions of the future necessarily means providing detailed description of them, but because these are not accompanied by maps close at hand (although some maps are included, even if poorly printed), the central thesis and the value of the comparisons between events in the two cities are, on occasion, lost in the density of the detail. This is not helped by the very long chapters, that each include detailed descriptions of what occurred in the cities, but do not easily facilitate comparisons between the events in both. Finally, the preferencing of detail means that on occasion the development of plans seems disconnected from the broader trajectory of historical events.

The sum result is a sometimes challenging text that leaves one wondering whether it could have been executed more directly and succinctly. Nonetheless, one must not underplay the book's value. There will be much to fascinate scholars of different backgrounds, particularly transport or urban historians, as this work challenges the reader to reconsider the trajectory of the relationship between railway construction and urban development and railway building in the two capitals, and how what is not built cannot infrequently illuminate our understanding of what was.