In “Ornaments of the Metropolis” (MIT Press, 248 pages, $39.95), Henrik Reeh, a Danish scholar, has written a book that is somewhat confusing and somewhat confused. Its subtitle, “Siegfried Kracauer and Modern Urban Culture,” gives you an idea of the fun that awaits the reader. And it may be that the confusion under which Mr. Reeh seems to labor, and that he inspires all too well in his readers, was rooted in the writings of his subject.

Kracauer, perhaps best known in America for his book “From Caligari to Hitler,” an analysis of German Expressionist film, was born in Frankfurt in 1889 and had close connections to such members of the Frankfurt School as Walter Benjamin, Theodor Adorno, and Ernst Bloch. Like them, he was bred into a world of abstractions that he could escape only by running to embrace still other abstractions.

If it were not the materialism of Marx that informed his thinking, it was apt to be some variation on the kind of sociological consciousness we associate with Max Weber and Georg Simmel. With this background in mind, especially the influence of sociology, we can understand Kracauer’s preoccupation with the city, a relatively new interest in the early years of the 20th century.

Kracauer was living in Berlin in the 1920s, at a time when, you could argue, it was the modern metropolis par excellence. Paris was eminent in many things, but pre-eminent really only in painting. In science, scholarship, and literature – not to mention several artistic movements of its own – Berlin occupied a status of centrality very close to what New York occupies today.

It is interesting to observe that, even though Berlin now has as much material wealth as it had then, and as many artists and professors, it has receded to the rank of yet one more European metropolis. In ways difficult to quantify or perceive, the implicit sense of centrality influences the very air we breathe in New York. This same air, this whiff of arrogance, of pride, of implicit confidence in the knowledge that one occupies the center, hung in the air over Berlin when Kracauer was living there.

Long before Hitler came to power and caused men like Kracauer, a Jew, to flee to Paris in 1930 (and to New York a decade later), intellectuals were acutely aware of the phenomena of urban life, especially of mass movements and what they saw as the collective mentality and behavior of city dwellers. If you consider the ways people have inhabited cities through the ages, or at least how they expressed themselves in surviving texts, it becomes clear that something new emerged in the megalopolis of the 19th century.

Augustan Rome was almost as big as 19th-century Paris or Berlin. But never, not even in satirists like Juvenal and Persius, did it achieve that intensely subjective responsiveness to urban life that we find in Baudelaire’s “Spleen de Paris,” in Doblin’s “Berlin Alexanderplatz” or, earliest of all, in Poe’s “Man of the Crowd.”

Kracauer’s initial contribution to the genre was an anonymous novel, “Ginster: von ihm selbst geschrieben” (Ginster: Written by Himself). But his views were articulated somewhat more systematically in those essays in the Frankfurter Zeitung that were later collected as “Strassen in Berlin und Anderswo,” and finally in a “sociobiography” of Jacques Offenbach. But what those views were is somewhat confused, as described in the present work.

Throughout his career, Kracauer was influenced by the notion of Ornament, which was a loaded term in Germany in the early 20th century, when Adolf Loos famously equated it with criminality and thus begat the Bauhaus. Kracauer, who wrote his doctorate on the decorative ironwork of Berlin, saw ornament as means by which humans interacted subjectively with the metropolis.

Or that appears to be what he thought. Despite Mr. Reeh’s efforts to clarify the matter, it was not clear to this reader to what extent Kracauer used “ornament” in its traditional meaning, and to what extent it had a very different and metaphorical meaning.

For example, in a work like “Das Ornament der Masse,” he reuses the term to refer – it would appear – to a particular kind of mechanistic and mass spectacle directly contrary to the subjective experiences of cities for which he, and Mr. Reeh, would seem to be rooting.

Though Mr. Reeh himself uses the term overwhelmingly in an abstract and metaphorical sense, by the end of his book, in a discussion of postmodern architecture, he has returned to using it in the most common sense of the word.

Matters are not helped by the author’s decision – perhaps unprecedented in a work of scholarship – to illustrate his book with about 40 of his own self-consciously arty black-and-white photographs. Though pleasant enough in their earnest way, they often seem to have little or no relation to what the book discusses. Meanwhile, buildings and monuments that are discussed receive no illustration at all, thus leading to still further confusion.