He has written four novels centred on the 16th-century spy Henry Gresham, the James Bond of Tudor times. Dr Stephen has also written and edited books on English literature, British warship design and sea battles.
The literary influence does not end there. Jilly Cooper told The TES that Dr Stephen was the inspiration for a "dreamboat headmaster" character in her school-based book Wicked!
Dr Stephen pledged last year that St Paul's would offer places to all pupils regardless of their parents' income by 2011. He has also called for a cadre of top teachers to teach only the brightest pupils. His only challenger to the title of most renowned public school head is Anthony Seldon, master of Wellington College, who has also criticised league tables. But Dr Stephen has lamented Dr Seldon's call for happiness classes.
Photograph: Chris Thomond.