I've got the opposite problems - I can't find books I know I've got (Wild Swan on the Wantage Tramway) and have lent books to people who don't give them back (One of Iain Rice's Wild Swan books about layout design)
I too sometimes can't find the ones I know I own - spent ages looking for the Euston - Watford DC lines signal Instructions and couldn't find them but I know they're there somewhere!! And don't tell me about buying duplicates although fortunately that only applies to a few less expensive copies.
