If it came to choosing between Gannibal: The Moor of Petersburg by Hugh Barnes and The Moor of St Petersburg: In the Footsteps of a Black Russian by Frances Somers Cocks, I'd go for Frances' excited take on it because she is not academic, has been irrepressibly jumpy about this for years, and unlike hugh's precocious and varied output, 'The Moor' has been the subject of all her published work (numbering: 2).