I have to thank various colleagues who have read proofs of this book, in whole or in part: first and foremost my old teacher, W. P. Ker; also Robert Priebsch, J. H. G. Grattan, Ernest Classen and two old students, Miss E. V. Hitchcock and Mrs Blackman. I have also to thank Prof. W. W. Lawrence of Columbia; and though there are details where we do not agree, I think there is ...