If this be grasped, its relations to other divisions of the work will be readily apparent and may be followed without difficulty.
This is the main idea on which the method pursued in these volumes is founded. The mode of treatment adopted is not arbitrary, or dictated by considerations of convenience. It springs from the nature of the subject and its difficulties. Specialisation is absolutely necessary for the study of history, and it is impossible for any one master mind to coordinate in one product the results of all the special work that is being accomplished around it. Elements of interest and suggestiveness, which are of vital importance to the specialist, disappear before the abstract system which the compiler must, whatever may be the scale of his undertaking, frame for his own guidance. The task is too large, its relations are too numerous and too indefinite, for any one mind, however well stored, to appreciate them all. It is better to allow the subject-matter to supply its own unifying principle than to create one which is inadequate or of mere temporary value. At all events, this work has been undertaken with a desire to solve a very difficult problem, and to supply a very real need, so far as was possible under the conditions of its publication.