What does it mean to "publish" a text? Is it merely to make it public (as says the oft-spoken definition)? As Bhaskar points out, leaving a manuscript on a park bench makes it public, but it doesn't "publish" it--nobody will read it. On the other hand, uploading a novel to Amazon without proper metadata "publishes" it, but doesn't make it public--it'll sink so low in the sea of data that no one will even know it's there.
In our networked age, Bhaskar argues, it's more important than ever for publishers to understand just what they do and why. But his basic outline of "publishing"--filtering, framing, and amplifying--applies not only to traditional publishers, but also to anyone who creates and distributes content, be it mp3s, TV episodes, news articles, recipes, web comics, or photos.
Bhaskar can't cover everything, but the swath of what he does cover is pretty staggering: believe it or not, he really does go "from the printing press to the digital network." As the prof who recommended it to me put it, "This is the book that the publishing industry has been begging someone, anyone, to write for years." And Bhaskar has done it brilliantly.