The RCAHMS was amalgamated with Historic Scotland in 2015.
The RCAHMS is a useful site for anyone looking to explore the history of particular buildings in Scotland online or in the government agency's search room at its Edinburgh base.
As well as authoritative and detailed reports written by conservation professionals, there are many excellent collections of documents and photos in the archive which can be viewed online. In fact, the archive has millions of photographs, maps, drawings and documents about buildings and landscapes, from prehistory to the present day.
Check site for opening times, if going in person.