This is an excellent book for all those who would guess that Bolt, Beranek and Newman is a law firm. It may sound like one, but it isn't. BBN - now a subsidiary of GTE/Verizon - is a company which is most intimately tied to the birth of what is nowadays known as the internet. And if the BBN's marketing guys would have been half as good as their engineers, we would probably hear a lot more about BBN today and less about, say, Cisco.
In a clear and highly readable style, Hafner and Lyon have covered the history of the packet switching networks with encyclopedic breadth. You'll learn both about the early theoretical fathers of packet switching, like Paul Baran and Donald Davies; you have the people in the DoD's Advanced Research Projects Agency (ARPA) like Joseph Licklider, Bob Taylor or Larry Roberts, who not only had a grand view of computer networking or obtained the necessary governmental funding, but were also able to specify their wishes precisely enough that the engineers were able to build the network based on their plans. And finally, there is Frank Heart's team at BBN, guys who actually built the darn thing.
The subtitle - The origins of the internet - is well chosen. Most of the book focuses on the years 1968-1972, from Roberts' draft proposal, to the 1972 international conference on computer communication. Other development, either earlier or later, is covered only fragmentary. There are other interesting stories, like the origins of USENET, internet news exchange service, but they are not the scope of this book.
The book leaves a pleasant impression that the authors actually understand the necessary technical background of the topic they are writing about. Some diagrams might help further, but I am sure that numerous metaphors used in the book will also alone help the casual reader to understand the idea of packet switching. Chapter notes and bibliography section deserve special praise, and the subject index comes in handy, too. Overall, a very satisfying book.