Don't buy it. That book is not informative. It's not worth the read. There is nothing to be seen.

• The title is "The Department of Mad Scientists: How DARPA Is Remaking Our World, from the Internet to Artificial Limbs". On the question of How, this book offers no revelation. Ultimately the book is not informative as a result.
• Obviously this world is a world of competing or missing ideas. If at all the DARPA is to be understood from point of view of the tax payer, it would be very relevant how particular - rather than other - ideas are chosen. Obviously, there is not just "the" prosthetic arm to be developed but there are - depending on amputation level - a number of concise and very important different issues. This book lacks all discrimination for all subjects mentioned. More importantly it would be important to understand how such an agency can ignore both previous research and body powered technology. It would be relevant to read why this is not a brotherhood of friends that give each other nice jobs and let that be it - because that is, quite frankly, what the DARPA comes across as. Geoffrey Ling saying that a prosthetic hook was something "out of Peter Pan"? Someone should explain how that could happen - after all the DARPA did an expensive arm prosthesis project, no? - and why Hosmer still has no new products. After all the DARPA were building something to entertain themselves for amputees?
• Also, an industry sized research agency gets ideas from somewhere. Where do these people get inspiration? Is the research process accredited given their size and funding? No answers on that. So we don't learn at all "how" the DARPA is remaking anything.

Please don't waste money buying that book. If you have to anyway, you have been forwarned.