Mr. Lanier’s book, which makes an impassioned case for “a digital humanism,” is only one of many recent volumes to take a hard but judicious look at some of the consequences of new technology and Web 2.0. Among them are several prescient books by Cass Sunstein, 55, which explore the effects of the Internet on public discourse; Farhad Manjoo’s “True Enough,” which examines how new technologies are promoting the cultural ascendancy of belief over fact; “The Cult of the Amateur,” by Andrew Keen, which argues that Web 2.0 is creating a “digital forest of mediocrity” and substituting ill-informed speculation for genuine expertise; and Nicholas Carr’s book “The Shallows” (coming in June), which suggests that increased Internet use is rewiring our brains, impairing our ability to think deeply and creatively even as it improves our ability to multitask.