Terence Albert Ladd Rees (24 February 1928 – 15 November 2014) was a microbiologist but was best known as a collector of material relating to the theatre and music in Wales and Britain. He was also a published theatre historian and researcher, and, in particular, was an authority on the works of W. S. Gilbert and Arthur Sullivan who, as Gilbert and Sullivan, wrote 14 comic operas in the late Victorian era.