Eugène Auguste Albert de Rochas d'Aiglun (20 May 1837 – 2 September 1914) was a leading French parapsychologist, historian, translator, writer, military engineer and administrator.
Rochas was born in Saint Firmin in the department of Hautes-Alpes, the son of Marie Joseph Eugène de Rochas d'Aiglun, a judge at the court in Briançon, and of Félicité Camille Jayet. He studied literature and mathematics at the Lycée de Grenoble, then, in 1857, entered the École Polytechnique in Paris, intending to follow a military career.
In 1861, he was commissioned as a Lieutenant in the Military Engineers ("Le Génie militaire") and distinguished himself as a soldier, engineer and administrator. He rose to the rank of battalion commander in 1880 and was made chief of engineers in 1887. He retired from the military in 1888 as a Lieutenant-Colonel. He had also been inspector of studies and director at the École Polytechnique but had to resign due to his involvement in paranormal research activities.
Rochas was made a Chevalier (Knight) in the Legion d'Honneur in 1875 and an officer in 1889.
As a scholar, he made significant contributions to the study of military engineering history, producing, for example, a French translation of an 11th-century Alexandrian treatise on fortification and machines of war called Veterum Mathematicorum Opera (1693), and publishing the correspondence of the distinguished 17th century military engineer, Vauban. He also wrote about ancient technology, exploring subjects as diverse as hydraulic organs, water clocks, ancient surveying instruments, temple machinery, Greek artillery, and ancient railways. He was well respected as a researcher and won a medal from the "Société des Études Grecques" for his translations of Greek texts.