This book is the publication of the manuscript written by José María ROman in 1808-1814 with another title. This is the only edition that exists, prepared by María Zozaya-Montes, with her own title, introduction, footnotes and glosary. An analysis of a part of the Peninsular war is here presented, that of the Spanish prisoners in France (1809-1814). That field has been little studied. Here is analyzed throughout a critical edition of a diary of one of those engineers. The introduction of the book allows us to understand how really the history of the suboficials (military and military engineers) was imprisoned during the Napoleonic wars. The gaze shows from the first person a completely different panoramic that of the one we used to have about prisoners.