This slim volume presents the final results of excavations at the Half Moon Battery which, attached by a wall to the cathedral church of St German, provides a good view of the southern half of Peel Castle and the harbour on the Isle of Man. The structural and artefactual evidence are used to examine the circumstances of the battery's construction towards the end of the 16th century (as defence against a Scottish-Spanish invasion), its use during the Civil War and its demotion to a mere viewing platform in the later 19th century.