Listmania!
The reference books I couldn't be without
The Chambers DictionaryThe Chambers Dictionary
The best one-volume dictionary there is - the standard for Crosswords and Scrabble. Indispensable.
Encyclopaedia Britannica 2006 Deluxe CD (Encyclopaedia)Encyclopaedia Britannica 2006 Deluxe CD (Encyclopaedia)
Buy new: £39.98 / Used from: £3.99
Once this filled a bookshelf and cost two months' wages, now it fits in your pocket and costs two hours' pay. The sum of human knowledge.
The "Times" Atlas of the World: Comprehensive Edition (Times Comprehensive Atlas of the World)The "Times" Atlas of the World: Comprehensive Edition (Times Comprehensive Atlas of the World)
Buy new: £103.13 / Used from: £142.46
You can buy cheaper atlases, but not better ones.
Chambers Biographical DictionaryChambers Biographical Dictionary
Buy used from: £3.05
The ultimate Who's Who - and Who Was.
The Chambers ThesaurusThe Chambers Thesaurus by Martin Manser
Buy new: £17.49 / Used from: £13.05
The finest example of just how much Thesauruses have improved since the days of Roget.
Whitaker's Almanack 2006 (Whitaker'S)Whitaker's Almanack 2006 (Whitaker'S) by ed. Inna Ward
Buy new: £24.45 / Used from: £0.99
Still quicker, better, more accurate and accessible than Google. A superb compendium of knowledge.
Brewer's Dictionary of Phrase And Fable 17th Edition (Brewer'S ...)Brewer's Dictionary of Phrase And Fable 17th Edition (Brewer'S ...) by ED
Buy new: £17.27 / Used from: £22.00
Delightfully eclectic, occasionally useless, often uniquely informative.
Chambers Dictionary of Quotations (Dictionary)Chambers Dictionary of Quotations (Dictionary)
Buy new: £16.50 / Used from: £2.35
For the purist, the Oxford dictionary is a better (and more expensive) bet, but Chambers is much more fun!
The Book of Lists: The Original Compendium of Curious InformationThe Book of Lists: The Original Compendium of Curious Information by Amy And Wallechinsky, David Wallace
Buy new: £2.44 / Used from: £0.01
Although never perhaps intended as a serious reference work, I never ceased to be amazed by how often I hoik this down from the shelf.
Guinness World Records 2006Guinness World Records 2006 by World Records Guinness
Buy used from: £0.35
Annoyingly useful