Louis Agassiz was a Swiss naturalist who made significant discoveries in geology and palaeontology. This book is his Recherches sur les poisons fossiles, a study of fossilised fish. It was illustrated mainly by the Austrian artist Joseph Dinkel as well as by Agassiz’s first wife, Cecile Braun. In gathering material for the work, which was published between 1833 and 1843, Agassiz travelled across Europe visiting collections that housed specimens. He was the only contemporary naturalist to officially recognise the discoveries of Mary Anning (1799-1847) at Lyme Regis, who he visited in 1834, naming the species Acrodus anningiae in her honour.

While producing the work, Agassiz noticed that many of the fish he was observing did not have the soft tissue of modern fish but were instead armoured or bony. This required the creation of a new classification system for fish specimens. It was a significant advance in ichthyology (the study of fish) but has since been superseded by new methods. In 1846, Agassiz travelled to the United States of America, where he would spend the remainder of his life.

While praised for his research into fish and his studies in glaciology, Agassiz has since been criticised for his support of the controversial theory of polygenism (the belief that humans consisted of two species, one 'white' and one 'black') and his opposition to the concept of evolution.