Scottish Language Dictionaries (SLD) have excellent information on Scots, present and past, in their dictionaries – see their website and the introductions to the Concise Scots Dictionary and the Scottish National Dictionary.

SLD also engages with the public and other interested parties through its outreach programme.

To celebrate its 10th anniversary, Scottish Language Dictionaries have held exihibitions at the Chapel Royal, Stirling Castle, Oxgangs Library in Edinburgh and the Members' Lobby of the Scottish Parliament.

The most authoritative dictionaries are those from Scottish Language Dictionaries published by Edinburgh University Press, unless otherwise indicated.

Concise Scots Dictionary (1985), a comprehensive one-volume dictionary covering the Scots language from its earliest records to the present, based largely on the two major historical works:
Scottish National Dictionary  (1931-76), 10 vols, from 1700 to the 1970s (published by Scottish Language Dictionaries), and:
Dictionary of the Older Scottish Tongue (1931-2002), 12 vols, from the earliest records up to 1700 (published by Oxford University Press).

The Scottish National Dictionary and the Dictionary of the Older Scottish Tongue are now available free on the Internet, as the Dictionary of the Scots Language,  at  http://www.dsl.ac.uk  A New Supplement bringing the language into the 21st century was added to the website in 2005.

Pocket Scots Dictionary (1988). Scots-English.

Scots Thesaurus (1990). Traditional areas of Scots vocabulary arranged thematically, with English-Scots index.

Concise English-Scots Dictionary (1993).

Essential Scots Dictionary (Scots-English, English-Scots) (1996). A small two-way dictionary, aimed  mainly at schools, but also a useful general reference work.

The Scottish Language Dictionaries website may be found at http://www.scotsdictionaries.org.uk/