One of two sf novels written by UK naval officer Geoffrey Martin Bennett using the 'Sea-Lion' pseudonym. Apart from a later Arrow paperback in 1963 this is the only edition of this novel. Both are very uncommon.

''pseudonym of UK naval officer and author Geoffrey Martin Bennett (1909-1983), whose two sf novels both deal with menaces at sea: The Invisible Ships (1950) indeed features invisible ships and THIS CREEPING EVIL (1950) features sea monsters and a threat to the UK'' (John Clute/Encyclopedia of SF, 3rd Edition).