While much has been said about the democratization of publishing through the rise of platforms like Amazon's Kindle Direct Publishing, little attention has been paid to the broader effect these technologies have had on writers, readers, and the publishing industry. In Content Machines, Sarah Brouillette considers how short-form, platform-based, and social media writing on digital mediums like Wattpad and TikTok has reshaped modern publishing, reading, and writing. Brouillette identifies three mutually reinforcing processes that platform capitalism entangles in the publishing industry: the marked feminization of book work; the rise of a bibliotherapeutic vocabulary that grounds reading and writing as self-care work; and the growth of platform-based processes that cheapen content and intensify the pressure to engage in self-promotion and entrepreneurial strategizing. She breaks down the business models that have been key to this transformation and traces the social conditions that make online self-published fiction, especially young adult, romance, and fantasy stories, into spaces for community while, conversely, signaling how these publishing practices depend upon undervalued and feminized labor from marginalized groups. Content Machines is a much-needed survey of the contours of the modern reading and writing landscape.