The London documents of 1814-1815 are of various degrees of interest and importance. Those relating to the Congress of Vienna are somewhat disappointing. Taken all together, they add less to our knowledge on the one or two points still requiring elucidation than the recently-published correspondence of Talleyrand with Louis XVIII. The despatches from Italy are on the other hand of great value, proving, what I believe was not established before, that the Secret Treaty of 1815, whereby Austria gained a legal right to prevent any departure from absolute Government at Naples, was communicated to the British Ministry and received its sanction. This sanction explains the obscure and embarrassed language of Castlereagh in 1820, which in its turn gave rise to the belief in Italy that England was more deeply committed to Austria than it actually was, and probably occasioned the forgery of the pretended Treaty of July 27, 1813, exposed in vol. i. of this work, p. 538, 2nd edit. [3] The papers from France and Spain are also interesting, though not establishing any new conclusions. While regretting that I have not been able to use the London archives later than 1815, I believe that it is nevertheless possible, without recourse to unpublished papers, to write the history of the succeeding thirty years with substantial correctness. There exist in a published form, apart from documents printed officially, masses of first-hand material of undoubtedly authentic character, such as the great English collection known by the somewhat misleading name of Wellington Despatches, New Series; or again, the collection printed as an appendix to Prokesch von Osten's History of the Greek Rebellion, or the many volumes of Gentz' Correspondence belonging to the period about 1820, when Gentz was really at the centre of affairs. The Metternich papers, interesting as far as they go, are a mere selection. The omissions are glaring, and scarcely accidental. Many minor collections bearing on particular events might be named, such as those in Guizot's Mémoires. Frequent references will show my obligation to the German series of historical works constituting the Leipzig Staatengeschichte, as well as to French authors who, like Viel-Castel, have worked with original sources of information before them. There exist in English literature singularly few works on this period of Continental history.