746 HARVARD LAW REVIEW

as much into the discussion of the English cases by which the fundamental principles of the law of future estates were estabUshed as does Kales' book. It is in the main what it purports to be, a summarized digest of the Illinois cases on this topic, which seem to be fairly numerous, with a good preliminary discussion of the general principles governing each topic as an introduction. On the whole it should prove a valuable aid to Illinois lawyers having business with this branch of the law. G. N. The Law as a Vocation. By Frederick J. Allen. Cambridge: Harvard University Press. Spirit of the Courts. By Thomas W. Shelton. Baltimore: John Murphy Company. [To be reviewed.] Tractatus De Bello, De Represalhs et De Duello. Edited by Thomas Erskine Holland. New York: Oxford University Press. [To be reviewed.] Constitutional Power and World Affairs. By George Sutherland. New York: Colimibia University Press. Income and Other Federal Taxes. Fourth Edition. By Henry Campbell Black. Kansas City: Vernon Law Book Co.