You are looking at a 1985 copy of 'Seas of Blood' by Andrew Chapman, which is #16 in the Fighting Fantasy series. This is the 1st edition. It's made attractive (or not!). by the distinctive Green Banner that was added to reissues around 1984-1985 in the series.
While this isn't the best fighting fantasy gamebook I have ever played it's not the worst either I wasn't expecting a great deal from this one but it is better than I thought it would be and that's why it gets 4 stars from me