"Law in books" refers to laws and legal doctrine contained in bound volumes, such as reporters. Roscoe Pound introduced the term in 1910 in contrast to “law in action” to illustrate the difference between how laws appear in text and their real-life application. This body of scholarship is often associated with legal realism, in which scholars who study law in books often critique legal theories and doctrines arguing that they do not accurately reflect how laws are used in practice.
The United States Constitution and Uniform Commercial Codes (UCC) are examples of law in books. They both outline basic principles of law; the Constitution lays out the basic principles governing the American legal system, and the UCC outlines a set of laws governing commercial transactions. That said, neither provides guidance on how to apply these laws in practice. For example, the Constitution guarantees a right to free speech; however, speech is subject to many limitations in practice. There is no guidance on how to apply these laws in practice. Similarly, the framework provided by the UCC for commercial transactions doesn't necessarily reflect how transactions are conducted in reality. These examples illustrate that law in books can reflect legal doctrines and principles but may not accurately convey how they are applied in real life.
[Last updated in July of 2023 by the Wex Definitions Team]