Gazetteers

Ordnance Survey Landranger Gazetteer – all names on the O.S. Landranger (1:50,000 or 2 cm one km) maps of Britain.

Note also:

Black, G.F., 1946, The Surnames of Scotland (New York; reprinted 1993, Edinburgh). An excellent survey of Scottish surnames, but also includes early forenames, and much of relevance to place-names, including surnames derived from places, and personal names contained in early place-names.

Ekwall, E., 1960, Concise Oxford Dictionary of English Place-Names, fourth edition.

Nicolaisen, W.F.H., et al., 1970, The Names of Towns and Cities in Britain, compiled by Margaret Gelling, W.F.H. Nicolaisen & Melville Richards, ed. W.F.H. Nicolaisen.

Place-Names on Maps of Scotland and Wales, Ordnance Survey: glossary of common Gaelic and Scandinavian place-name elements (latest edn. 1981, price £5.70).

PLACE-NAME ELEMENTS: There is a series of Ordnance Survey web-based publications for three of the languages which have made an important contribution to the place-names of Scotland: Gaelic, Scandinavian (Norse) and Scots. Each consists of an Introduction, which includes some basic grammar as it relates to place-name formation, and a Glossary of common place-name elements.

The pdfs with Introductions, can be downloaded as follows:

SCOTLAND

For Gaelic Place-Names (Introduction by Simon Taylor):
https://getoutside.ordnancesurvey.co.uk/guides/the-gaelic-origins-of-place-names-in-britain/

For Scandinavian (Norse) Place-Names (Introduction by Anke-Beate Stahl):

https://getoutside.ordnancesurvey.co.uk/guides/the-scandinavian-origins-of-place-names-in-britain/

For Scots Place-Names (Introduction by Simon Taylor):

https://getoutside.ordnancesurvey.co.uk/guides/the-scots-origins-of-place-names-in-britain/

There is a fourth such site concerning Welsh Place-Names:
The Welsh origins of place names in Britain | OS GetOutside (ordnancesurvey.co.uk)

Although each of these four sites includes the word ‘Britain’ in its title, in the first three read ‘Scotland’ for ‘Britain’, in the fourth read ‘Wales’.

Warning: Most of the more popular guides and dictionaries are written on the basis of unsound methodology and information, and are best avoided. This includes almost any small, one volume work covering the whole of Scotland. Two exceptions to this are: Alison Grant’s The Pocket Guide to Scottish Place-Names (Glasgow 2010); and Maggie Scott’s Scottish Place Names (2008). A problematic example is J. B. Johnston, Place-Names of Scotland (1934). It is often seriously off the mark when dealing with etymologies, but it does contain early forms of names (unfortunately not usually sourced).

Bibliography:
Spittall, J. & Field, J. 1990, A Reader’s Guide to the Place-Names of the United Kingdom (1920-89) (Stamford): a bibliography of publications (1920-89) on the place-names of Great Britain & Northern Ireland, the Isle of Man, and the Channel Islands.