The question of identity-who exactly are we at any given time and place?- has been a favourite topic of debate in postmodernist circles for decades.

Tom Reiss’s new book is the story of one man who posed the question and answered it in his own original way. Lovers of exotic novels know the man under the pen-name of Kurban Said. Others know him as Essad Bey, the author of a number of political biographies including one on Stalin and another on Reza Shah the founder of the Pahlavi dynasty in Iran.

Now, however, Tom Reiss reveals that not only Kurban Said and Essad Bey were one and the same person but that both were emanations of a third, well-hidden, identity.

Reiss was put on this fascinating track a decade ago when he first visited Azerbaijan, one of the newly-independent mini-states emerging from the debris of the Soviet Empire. In Baku, the capital of Azerbaijan, he was presented with the novel “Ali And Nino” as the greatest example of Azeri literature. Soon, however, he found out that “Ali And Nino” had been written in German and published in Austria before the Anschluss in 1938. An English translation of the novel had appeared in 1971. (Reiss did not know it but a Persian translation of the book had also appeared in Iran in 1975.)

But who was Kurban Said?

In Baku, Reiss heard many stories about the mysterious man, none convincing. Soon he found that Kurban Said had appeared exactly at the time that Essad Bey had faded. But why? After five years of travel, research, countless interviews and chance encounters Reiss solved the mystery. Kurban Said and Essad Bey were two personas that one Lev Nussimbaum had invented for himself to get by in a dangerous world. Lev had been born into a Ukrainian Jewish family. His father had been an oil baron when Baku was the centre of the biggest oil boom in history. His mother, who had died in his infancy, however, had been a Bolshevik and, briefly, an associate of Josef Stalin.

As a boy Lev became fascinated with Azeri Muslim culture of the Caucasus and dreamed of “becoming one of them”. The conquest of Azerbaijan by the Bolsheviks in 1921 forced Lev and his father into exile first in Central Asia and then in Iran and eventually in Turkey. After brief sojourns in Italy and France, the two Nussimbaums ended up in Berlin which had become the gathering place of Russian refugees from the Bolshevik Revolution.

Thanks to his German nurse, young Lev was fluent in German and somehow bluffed his way into the prestigious School of Oriental Studies in Berlin even before completing his secondary education. To get into the school he had had to invent a new identity for by becoming Essad Bey, a “Tatar Muslim of princely origin”.

Lev loved his new identity so much that he started dressing as a Tatar, even wearing a turban and a dagger on his cummerbund. He also started writing sensational books about the Soviet secret services and the threat of Bolshevism to mankind. Before he had turned 25 Lev, alias Essad Bey, had become an acknowledged “expert on the Orient”, and a best-selling author whose exotic dress and behaviour attracted attention from the tabloid press.

By the mid-1930s Essad Bey was something of a star on both sides of the Atlantic, his books appearing in 17 languages. He was also married to a ravishing Czech beauty with a rich father. But as luck seldom holds, the peak of Essad Bey’s glory also coincided with the rise of Hitler to power in Germany. It didn’t take the Nazis long to discover Essad Bey’s Jewish origins and put his name on the black list of authors. He was soon abandoned by his wife who also mocked his “Jewish origins” in tabloid interviews. Forced to flee first to Vienna and, after Austria was annexed by Hitler, to Italy, Essad Bey died of a strange disease in a forlorn hotel in the seaside resort of Positano.

In his final years, unable to use the name Essad Bey, he invented the pen-name of Kurban Said for two novels written solely to gain some cash. The novels revealed a much greater talent in fiction than in the factual books he had authored under the name of Essad Bey.

Rees’s book is not a biography in the classical sense. It is more of a journey in search of someone that Reiss has obviously grown to love and admire. Along the way Reiss meanders into many different subjects- from the oil boom of Azerbaijan to the rise of Mussolini in Italy and passing by the theology of the Yazidis in Iraq and the big power rivalries in Central Asia and Iran. We also learn a great deal about German Jews who, in a sense, invented modern Germany only to see it become a killing machine against them.

Reiss implies that Lev Nussimbaum never really abandoned his Jewish faith and that his conversion to Islam had been a pose. But he cites no evidence for this. On the contrary it seems to me that Nussibaum was sincere, insofar as a cultural cross-dresser is capable of sincerity, in his civilisational switch from Europe to the Orient and from Judaism to Islam. Seen in context this need not be surprising. The last decades of he 19th century produced numerous European Jewish intellectuals who saw themselves as Asians and dreamed of forging an Islamo-Jewish axis to resist the advance of the Christian West. One of the most prominent among them was Benjamin Disraeli who rose to become Prime Minister of Great Britain. His novel “Coningsby” is based on precisely the dream of Judeo-Islamic axis in Asia.

In one of his letters Essad Bey complains that the Europeans would never accept him as one of them. “ With Muslims, however, I am always welcome as a newcomer to the family.”

One sign that Essad Bey was sincere in regarding himself as a Muslim is that he insisted that his tomb in Positano be placed in the direction of Mecca and that his tombstone be inscribed in his adopted Muslim name not his Jewish birth-name.

This is a fascinating book that could be read as a thriller.