Just finished 'Smoke and Mirrors' by Deborah Lake (Sutton, 2006). Absolutely first class account of Q-ships and their actions against the German U-boats in WW1; kicks off with an excellent survey of the origins and development of the submarine up to 1914. btw I picked this up for a song in one of Galloway and Porter's last-Saturday-of-the-month warehouse clearance sales in Cambridge last year. Always worth a look if one is in the area, although far from the sea there is often naval and particularly Nelson stuff going cheap. Very cheap. But one has to navigate through shoals of pointless chick-lit and tons of remaindered gardening and cooking books to find it sometimes. Cheap but not-quite-so cheap remaindered miltary and naval stuff in their main shop in Cambridge also. Worthwhile to scan the history shelves at Oxfam two doors down too.