Career
He worked in Sotheby"s department of historical and literary manuscripts. After the winning of Winston Churchill Travelling Fellowship he wrote a book on Armenian history which was reissued in 1990. In 1975 with the support of "Minority Rights Group" he published "The Armenians" report (co-author - Professor David Marshall Language).
In November, 1989 at the Oxford University Walker had a lecture on the modern history of Armenia.
He has also written several books and articles on history of Armenia. One of his most famous works is Armenia: The Survival of a Nation book, which was appreciated as an "excellent history of Greater Armenia" and "a balanced presentation" of the events during the Armenian Genocide of 1895-1918.