A Naturalist in Indian Seas, or, Four Years with the Royal Indian Marine Survey Ship Investigator is a 1902 publication by Alfred William Alcock, a British naturalist and carcinologist. The book is mostly a narrative describing the Investigator's journey through areas of the Indian Ocean, such as the Laccadive Sea, the Bay of Bengal and the Andaman Sea. It also details the history of the Investigator, as well as the marine biology of the Indian Ocean.