I'm not sure the reviews so far are terribly helpful if you want a quick feel for whether to read this book or not. So here goes.
It's basically a bravura sweep through the history of information, told with great panache and lots of anecdote, mixing straight narrative with reflection on wider significance, and attempting to explain quite difficult concepts for the non-specialised reader. Whatever else it may or may not be, I found it a lively and enjoyable read.
The book falls broadly into three sections. The first runs through key early stages in the creation, storage and use of information - the alphabet, printing, the telegraph, telephone, etc. I didn't find much new here but the author did a great job marshalling facts, figures, characters and anecdotes into a lively tale.
The heart of the book grapples with information as a scientific concept, and you will find yourself in the realm of computers, information theory, DNA and quantum mechanics (to name but a few). This isn't natural territory for me, but I was swept along by Gleick's style and even felt I understood some of the underlying mathematical concepts he sought to explain.
The final section is essentially a thought piece on the modern information age, considering the ubiquity of information from the internet and the perils of information overload. Rather like the first section, I didn't feel there was a great deal new here but Gleick's ability to call up literary references, make parallels across the centuries and ask the pertinent questions made it an engaging read. I'm certainly pleased to have made the acquaintance of Vincent of Beauvais, a thirteenth century monk who seems to have arrived 750 years early for the Information Age.
So, a dazzling read certainly, but one also with a great deal of substance. Recommended.