The book focused on the invention of the first ereader, the Cyberbook. It was more of a satirical take on the publishing industry than a prediction of the near future, but that just renders the accuracy all that much more amazing. Here's the money quote:
"Cyberbooks will bring down the cost of publishing to the point where thousands of writers who can't get their works published now will have a viable marketplace for their books".
Doesn't that sound like the current state of self-publishing?
While it's not clear that Mr. Bova predicted that so many would bypass the traditional gatekeepers, there is still a ring of truth to this. Would you believe it was just tossed off in a brief phone conversation near the end of the book? And there's even more predictions in the book which have come true, including online sales and the amount of effort publishers put into resisting change.
Just to put this into perspective, Cyberbooks was published the year before the first Sony Data Discman hit the market. That was the first device to even come close to the ereader described in the novel, but it still fell short.
If anything, Mr. Bova was probably inspired by the DynaBook, a theoretical tablet/ereader developed by Alan Kay in the late 1960s. The Dynabook, which bears striking resemblance to the Kindle DX, was supposed to have very long battery life and was conceived as way for children to gain access to digital media. (Of course, that last detail is amazing all on its own; digital media itself didn't exist at the time.)
You can look at the Dynabook and see that it was the godfather of all ereaders, but the one device that comes closest to the original ideal would probably be the XO laptop from One Laptop per Child. It's bigger and heavier than the concept, but it is does follow the spirit of the idea.