Depths (original title: Djup) is a 2004 novel by Swedish writer Henning Mankell. Set in 1914 and 1915, the novel concerns a naval engineer Lars Tobiasson-Svartman, on board the Swedish navy's Coast Defence Ship Svea, undertaking a covert mission to find and chart navigable channels through the Stockholm archipelago. During the voyage Svartman alights on a barren skerry, and discovers a young woman there, Sara. Despite her feral nature, something about her strikes him to his core and, even when he has returned to Stockholm and his wife Kristina, he finds himself compelled to go back to the island.