The so-called 'Assassins' are one of the most spectacular legends of medieval history.
In the popular imagination they are drug-crazed fanatics who launched murderous attacks on their enemies, terrorising the medieval world.
Since the tales of Marco Polo and others, the myths surrounding them have been fantastically embellished and the truth has become ever more obscure.
Universally loathed and feared, they were especially frightening because they apparently had no fear of death.
Bartlett's book deftly traces the origins of the sect out of the schisms within the early Islamic religion and examines the impact of Hasan-i-Sabbah, its founder, and Sinan - the legendary 'Old Man of the Mountain'.
This popular history follows the vivid history of the group over the next two centuries, including its clash with the crusaders, its near destruction at the hands of the Mongols, and its subsequent history.
Finally, and fascinatingly, we discover how the myths surrounding the Assassins have developed over time, and why indeed they continue to have such an impact on the popular imagination.