Ernie Smith's Motherboard article on the early years of DRM gets into some fascinating stories about things like IBM's Cryptolope and Xerox PARC's Contentguard (which became a patent troll), Intertrust's belief that it is "developing the basis for a civil society in cyberspace" and the DeCSS fight.
As interesting as it is, it has some pretty glaring omissions, like the 1979 internal battle at Apple over DRM, the passage of the DMCA in 1998, the jailing of Dmitry Syklarov over breaking Adobe Ebook DRM, the legal threats against Ed Felten and USENIX over SDMI, and the Sony Rootkit, which saw a multinational firm disgraced and fined tens of millions of dollars for its DRM deployment.
Specifically, one company, made up of a whole lot of academically-minded engineers, lined the roads on which a lot of secured content would drive down. That company was called Electronic Publishing Resources, Inc., a firm that used the words "middleware," "container," and "encryption" to describe its earliest attempts at the creation of DRM.
The firm was founded by a guy named Victor Shear, who built his name in the information management sector. In the 80s, he was the head of a Maryland company called Personal Librarian Software, which produced a database management system that could effectively manage historic information. This company, which mostly served large corporations, exposed some of the earliest roots of digital rights management, as it Shear's company pondered ways to limit access to different kinds of information.
The Incredibly Technical History of Digital Rights Management