Although most of my office books are physics or math, I'm going to take a broad tour of covering mostly non-technical books and ones that are maybe a little out of the ordinary. I'll leave links out of this, all of the books are available new or used on amazon.com and amazon UK (Sheppard).
Engineering in Emergencies, Davis and Lambert
This is an engineering and logistics guidebook for humanitarian workers. Though focused mostly on 3rd world, non-hazardous duty, humanitarian efforts, there is quite a bit which is relevant to general expedition planning, scientific expeditions, and directed 3rd world work such as photojournalism or documentary film-making.
Vehicle-dependent Expedition Guide, Sheppard
The final word, until the next edition, on getting around to interesting and odd places using a vehicle, well, a 4x4 truck anyway. The book is more than just a tad bit British, but it covers all of the bases and is the book used by Land Rover for their classes. Some equipment availability is different in the US, and the high-tech items move from cutting-edge to obsolescent much quicker than a book could document them, but otherwise we have a beautiful piece of work here.
Traveler's Handbook, Globe-Pequot
This is an interesting and unexpected little volume. The book consists of two sections, the first is a series of essays covering most any imaginable type of travel, dealing with customs, photography, traveling solo, etc. and the second part is a series of facts, recommended readings, and so on. The former are brilliant, with some essays (such as the traveling artist and overland through asia) that are inspirations. The second part of the book is mostly worthless with the internet available. Who would guess that what looks like the most general possible travel book would actually be excellent?
Wiley Encyclopedia of Energy and the Environment, Bisio and Boots
Two volumes covering the hugely important area of Energy (generation and consumption) and the Environment (effects and mitigations). Obtained this back when I was teaching an Energy and the Environment class, this continues to be a useful reference.
Jane's Mines and Mine Clearance & Brassey's Essential Guide to Anti-Personnel Landmines
Here they are being used as more than military gear porn. I have been interested for a long time in humanitarian demining, especially using modern sensor technology (ground-penetrating radar and neutron-backscatter in particular). A worldwide health crisis that largely kills below the TV horizon.
The Topos of Music, Mazzola
Truly a strange book that I have not spent enough time with. Subtitled, Geometric Logic of Concepts, Theory, and Performance. 1300+ pages and a CD-ROM.
Cosmic Rays at Earth, Grieder
A massive compilation of cosmic ray observational data, but NO CD!!! No website with the data collected, just pages and pages of graphs. Useful, but limited by a lack of electronically available data.
Short Speeches & Born Again & Fly & A New Species etc., Lawson
Alfred Lawson. An interesting character. Invented, in the real world or his own mind, major league baseball, the airline, the airliner, regularly scheduled airplane flights, the great novel of the 20th century (Born Again), a morally acceptable alternative to the banking system, a new religion (Lawsonomy), the only university needed (of Lawsonomy), and organic gardening. Wow! Lots of life and history, albeit almost all of a terminally weird nature, in there. Also worth looking at is the biography of Lawson and his ideas, Zig-zag-and-swirl by Lyell Henry.