In this NBER monograph, Zorina Khan describes the evolution of thought on the subject of intellectual property in the United States from the early Federal period to 1920 and compares the institutions that emerged with those that had been established in Britain and France. An underlying theme is that the democratization of intellectual property rights, roughly interpreted as the widespread access of men and women from all walks of life to protection for their ideas, created an environment that promoted invention and ultimately led to higher rates of economic growth. The term “democratization” has recently itself become something of a “catch-all,” often used to represent some intangible social characteristics that may affect economic growth, political processes, credit markets, and a host of other outcomes. But here the author supplies substance to the notion by bringing to bear a wealth of information, both new and culled from her previous work, about the extent of patent applications, grants, and litigation in the United States.

The result is a comprehensive account of how technological progress occurred at the grass-roots level. There are no sweeping “general purpose technology”-type events here, but rather a gradual progression of knowledge facilitated by a seemingly benign U.S. patent authority that allowed returns for innovative thinking to accrue not only to great inventors, but to creators of more mundane accomplishments as well. In contrast, the systems that evolved in Europe are characterized as being concerned with ensuring property rights for the elite. Although the European system may have reduced the number of trivial inventions passing through the patent authorities, it also tended to favor large technical inventions rather than other useful ones that did not require as much expertise. The author argues convincingly that the resulting intellectual property system did not fuel further invention as much as might have been possible.

Khan proceeds to explore trends in patent litigation as well, concluding that courts in the United States were for the most part able to balance effectively between encouraging invention and not simply affirming indefinitely the market power of patent holders. In an interesting twist, she cautions against blind acceptance of the conventional view that U.S. courts made somewhat arbitrary decisions when enforcing patents before the major legislation of 1836 and became more inventor-friendly thereafter. The main point is that restricting attention to actual court decisions can lead to inferences about patent stance that are based only on unrepresentative samples of apparent infringements. By observing instead that earlier court decisions tended to be cited proportionally as much as later ones, the author demonstrates that a clear turning point in judicial attitudes towards patents across the mid-nineteenth century is unlikely. Rather, patent rights included in the original U.S. Constitution and their implications for the democratization of invention were internalized by the courts throughout the first 130 years of the nation's history.

Two chapters on women inventors and the property rights of married women are among the more novel in the book. The author here points out that women could access the U.S. patent system about as easily as men could, and shows that increasing numbers of women took advantage of it over time. Though based on small samples compared to the wealth of general patenting data analyzed in earlier chapters, Khan nonetheless offers evidence that the growth rate of patents granted to women became higher than that for men as the nineteenth century progressed. Such a result immediately raises questions of why this was the case. Were women simply becoming more creative relative to men? Or, perhaps more likely, did women increasingly overcome the financial barriers to obtaining patents, leading to the release of a backlog of good ideas? Or did women benefit from a legal environment that became more sympathetic to their claims? These questions are not addressed in any depth, with focus instead on how the household had become a locus of invention and innovation. Other researchers, however, will no doubt be motivated by these chapters to attempt to tackle some of these larger questions.

Khan also argues that the stance of the U.S. courts towards copyright infringements differed considerably from the systems existing in Europe. She portrays the United States as a leader in this regard, arguing that by not providing excessive protection to the contents of the printed page, the nation eased frictions that would otherwise have existed in the dissemination of knowledge. The emphasis on not depriving the public domain of important resources seems almost a forerunner of the democratization of knowledge encouraged by the internet today.

I would recommend this book to anyone interested in a quantitative account of the path and patterns of technological change in the nineteenth-century United States. With a nearly exclusive focus on formal measures of innovation such as patents and copyrights, however, the forest never seems to come into full view. Indeed, a macro economist might even step away from the monograph with a view that innovation and technological change are incremental processes that are surprisingly well captured by the “A” parameter of standard growth models. But there are others, including this reviewer, who see technological changes as more lumpy processes that sometimes arrive with a flourish and offer new ways to think about the very act of inventing. Steam, internal combustion, and electrification may well be examples of such technologies. In this alternative world it is the importance of particular innovations and their association with a leading new technology that matter for understanding how innovation affects long-run outcomes, and these dynamics are not well captured by patent counts. More work may be able to integrate the two approaches, and I am confident that more strong contributions by this author and others will in the end achieve it.