For fans of Mythbusters, the little black book aptly called Pocket Ref is perhaps the most used tool on the show.
Pocket Ref is a book published by Sequoia Publishing, and is now in its third edition, which is a testament to its continued usefulness. It contains reference information of all types, as well as tables, charts and guides on such varied subjects as automotive repair, carpentry, construction, chemistry, physics, computers, physical, chemical, and mathematical constants, electronics, money and measurement conversions, first aid, glues, solvents, paints, and finishes, hardware, mining, milling, and aggregate, plumbing, zip codes, rope, cable, and knots, steel and metals, surveying and mapping, geology and mineralogy and much more.
Some of the information I've found in it so far has been simply mind-blowing! As the publisher indicates, they have made every attempt to avoid any errors, and I can appreciate how difficult it would be to complete this task with any degree of success. The book has been in print since 1989, and as mentioned above, is currently in its third edition (and according to my copy, the 24th printing!). The latest edition was released in 2002, and I would imagine that any errors that were discovered have been reported and corrected since then in subsequent printing runs. I have found a few omissions (specifically area codes for the Montreal and Toronto area, but the base ones listed are correct), and a decidedly USA-centric base of knowledge, as exposed by details such as the fact that most measurements are imperial unless specified, or that listed military ranks are in fact US Army, Navy, Air Force and Marines. But in no way does this reduce the value of this book.
As the name implies, Pocket Ref is a pocket-sized book and can truly be carried with you all the time, and its priced low enough to make it an excellent gift for any person on your list. It is also possible to order copies with custom covers, making this an excellent business gift for prospective customers. Trust me, they will remember you forever if you give them one of these with your business contact information printed on the cover. This book is easily one of the three books I would choose to take with me to a deserted island, and might even make my number one pick, if I was thinking rationally!! Get your own copy now, you will definitely not regret it.