The Military Balance has been published by the International Institute for Strategic Studies since 1959. The Publication divides the world into geographical regions and major political alliances then analysis by country the armed forces this includes strategic nuclear assets, army, navy airforce and any paramilitary organisation at the level of numbers of major units, numbers of major equipments, numbers of personal. Major units vary depending on the size of the army, for the larger forces divisions by type for smaller armies brigades and battalions.
For NATO and Warsaw pact countries it allows you to identify the major equipments used for smaller countries it is potentially more useful as the smaller numbers of equipments can be more easily related to the organisations. It provides a good indication of the equipment owned and is always an excellent starting point for any new modern war-games project.
The books are published annually and there are significant numbers available second hand, which is just as well as the cost of the latest one is generally prohibitive. Second hand they are more reasonable. I have a collection covering a spread of years across the 80's 90's and 00's. Exemplar data can be found here which is indicative of the information published on each country.
Military Balance 1981-82
Military Balance 1984-85
Military Balance 1986-87
Military Balance 1990-91
Other Book Reviews
Soviet Air Land Battle Tactics
Encyclopaedia of the Modern British Army
The Soviet Conduct of Tactical Manoeuvre
The Third World War
The British Army in Germany
The Cold War Bookstore contains links to over 60 Cold War titles covered in my book list