Jak P. Mallmann Showell's first book (U-boats Under the Swastika) is one of the longest selling naval books in Germany and his second (The German Navy in World War Two) was named as one of the outstanding books of the year by the United States Naval Institute. His research is based exclusively on original documents such as logs, personal accounts written shortly after the events and interviews. His reviewers have named him as being 'the respected authority'. Jak has been awarded the Silver U-boat Badge by the German Submariners' Association in Munich. He has also presented lectures at special Battle of the Atlantic weekends and has helped with the production of TV and radio programmes.