Sir Charles Oman’s History of the Peninsular War, Vols. 3 and 4 (Oxford, 1908 and 1911), is still an excellent guide to the campaign. The Dispatches of Field Marshal the Duke of Wellington (London, 1838) and the Supplementary Despatches, Correspondence, and Memoranda of Field Marshal Arthur Duke of Wellington (London, 1860) are essential as published documents of the campaign. William Napier’s History of the Peninsular War (London, 1835) should be used with caution. British participants have left valuable personal memoirs and letters that have been published and many are quoted in the text. For complete titles, see the excellent bibliographies in Paddy Griffith, ed., History of the Penninsular War: Vol. IX, Modern Studies of the War in Spain and Portugal, 1808–1814 (London, 1999), Oman’s Wellington’s Army and the general indexes of the Journal of the Society for Army Historical Research. John Grehan’s The Lines of Torres Vedras (London, 2000) and A. Norris and R. Bremner’s The Lines of Torres Vedras (Lisbon, 1980) ably cover that subject.
The British army is well covered in Oman’s Wellington’s Army (London, 1913) and in Philip J. Haythornthwaite’s The Armies of Wellington (London, 1994). Regimental histories of the various British regiments involved all cover their unit’s participation. John Elting’s Swords Around a Throne (New York, 1988) is one of the best works dealing with Napoleon’s troops. There are few works in English on the Portuguese forces besides Andrew Halliday’s The Present State of Portugal and of the Portuguese Army (Edinburgh, 1813) and the author’s Portuguese Army of the Napoleonic Wars (Osprey Men-at-Arms Series, Nos. 343, 346 and 356).
There are few published French sources on this campaign. A good overview from the French perspective is in A. Hugo’s France Militaire, Vol. 4 (Paris, 1837). Of the French memoirs, Baron Marbot’s is perhaps the most revealing. Correspondence and biographies of marshals Ney and Masséna are important if focusing more on their mutual disputes than on the campaign. French statistics should be used with caution because of obvious exaggerations.
In Portuguese, essential data for the 1811 campaign is found in Simao José da Luz Soriano’s Historia da Guerra Civil … Guerra da Peninsula, Vol. III (Lisbon 1874). Christovam Ayres de Magalhaes Sepulveda, Historia Organica e Politica do Exercito Portugues, Vols. XI–XIII (Coimbra, 1916–1925), has excellent documents and compilations. Claudio de Chaby’s Excerptos Historicos e Colleccao de Documentos Relativa a la Guerra Denomida da Peninsula …, Vols. III to VI (Lisbon, 1865–82) is somewhat dated but still very useful. Ferreira Martins’ Historia do Exercito Portugues (Lisbon, 1945) is the standard history of the army. A good overview of the army and the campaign is given in Carlos Selvagem, Portugal Militar: Compendio de Historia Militar e Naval de Portugal (Lisbon, 1931, reprinted 1999), a classic compilation of Portuguese military history on land and sea.
Additional sources are detailed in the footnotes.