In reply to Greenbanks:
Right now for oldest etc:
Oldest: Both Haskett Smiths 1895 and 1895 and Laycock 1913
Favourite: Just has to be Laycock, I'm a gritstoner, but find a copy of Rock Climbs round London, H Courtney Bryson 1936 - a brilliant read and hilarious.
Obscure: There are so, so many but try these
A Climbing Guide to Pen Penmaen Llanfairfechan, 1950, Renshaw and Lewis (3 copies printed, one know to exist). I have a pdf of the update version from the 1970's.
Doe Grag, 1922, note the spelling, obviously a mistake that was corrected as most have Dow Crag on the cover.
Almscliff A Key to Climbs, 1949 ish, Harry Stembridge, one copy is know to exist, it's in Australia because I was out bid for it.
Mossy