H.M.S. Unseen is a naval thriller published in 1999 by Patrick Robinson; it is the third book in the series featuring Admiral Arnold Morgan, and marks the return of Ben Adnam. It is stylistically similar to Tom Clancy, particularly his The Hunt for Red October. The book differs from the previous two in the series in that it focuses less on the plot and heroes and spends more time on the character development of villain Ben Adnam. Source: Wikipedia (en)