At various points in this book I have drawn attention to the limitations of the evidence available to the student of Rump politics. In seeking to make use of that evidence, I have found myself applying techniques of investigation some of which do not seem to have been previously adopted. They do not represent any seminal methodological breakthrough: they would, I think, suggest themselves to anyone confined by the same material. But they could perhaps be used to advantage in studies of other periods of parliamentary history. The specialist reader will want to know something of them if he is to trust certain of the references given in my footnotes to supporting evidence. Other readers may also, I hope, find interest in the observations which follow.

The chief difficulty in studying Rump politics is not the amount of available evidence but its nature. There is plenty of institutional, formal evidence. What is in short supply, at least by comparison with the evidence for the earlier years of the Long Parliament, is a fund of informal material - of diaries, letters and memoirs - to give flesh and blood to the dry bones of institutional records, to tell us not only what men did but why they did it. It is interesting to speculate on the reasons for this relative dearth. The fashion for compiling parliamentary diaries, prevalent in the earlier 1640s, seems to have died out well before the Rump period. Many politicians who have bequeathed private papers were excluded from power, and hence from an intimate knowledge of political developments, after Pride's Purge.