Ordnance survey of Scotland.
Caledonian Books.
Ellon :  Caledonian Books, 
1987-.
Reproduction of O.S. 1" of Scotland, edition of 1896.
Some maps have additional railway information added for dates between 1897 and 1903.
Those maps covering the Outer Hebrides, Orkney, Fair Isle and Shetland have been published on a revised layout, essentially adhering to the numbering system, but with re-cast sheet lines combining previously separate maps under one number, on sheets usually larger than the originals.