6 books
Oliver Cromwell and the Rule of the Puritans in England...
Scotland and the Protectorate. Letters and Papers Relating to the Military Government of Scotland from January 1654 to June 1659. Edited with Introd. and Notes
Stuart Tracts, 1603-1693; With an Introd. by C.H. Firth
The Teaching of History
The Last Years of the Protectorate, 1656-1658 Volume 1
The Parallel Between the English and American Civil Wars. the Rede Lecture Delivered in the Senate House, Cambridge, on 14 June 1910