This work investigates the historical reality of Prince Henry the Navigator, questioning the construction of his reputation as a singular pioneer of the Age of Discovery. P. E. Russell, a distinguished historian of Portugal, utilizes extensive archival research and contemporary primary sources to dismantle the myth of the 'Navigator' as a visionary scientist. He argues that Henry's motivations were primarily rooted in medieval crusading ideals and dynastic ambition rather than the modern scientific curiosity often attributed to him by later nationalist historiography.

Historians regard this text as a definitive corrective to romanticized accounts of Portuguese exploration. Scholars frequently cite the book for its rigorous methodology and its success in separating historical fact from the cultural myth-making that defined Henry's legacy for centuries.