At the beginning of America's involvement in World War II, Galveston Island was a recreation center for area servicemen. Every evening throngs of soldiers, sailors, and Marines strolled along the seawall, basking in the warm sun and soft gulf breezes. Red, pink, and white oleanders bloomed in all their glory, sea gulls squawked overhead, and gentle waves swished over sandy beaches. It was paradise on earth. Small wonder that German U-boat commanders...