Although Harold Lamb wrote short stories for a variety of magazines between 1917 and the early 1960s, and wrote several novels, his best known and most reprinted fiction is that which he wrote for Adventure magazine between 1917 and 1936. The majority of Harold Lamb's work for Adventure was historical fiction, and can be thematically divided into three broad categories of tales:

• Stories Featuring Cossacks
• Stories Featuring Crusaders
• Stories with Asian or Middle-Eastern Protagonists

Lamb's prose was direct and fast-paced, in stark contrast to that of many of his contemporary adventure writers. His stories were well-researched and rooted in their time, often featuring real historical characters, but set in places unfamiliar and exotic to most of the western audience reading his fiction. While his adventure stories had familiar tropes such as tyrannical rulers and scheming priests, he avoided the simplistic depiction of foreign or unfamiliar cultures as evil; many of his heroes were Mongolian, Indian, Russian, or Muslim. Most of his protagonists were outsiders or outcasts apart from civilization, and all but a very few were skilled swordsman and warriors.

In a Lamb story, honor and loyalty to one's comrades-in-arms were more important than cultural identity, although often his protagonists ended up risking their lives to protect the cultures that had spurned them. Those holding positions of authority are almost universally depicted as being corrupted by their own power or consumed with greed, be they Russian boyars or Buddhist priests, and merchants are almost always shown as placing their own desire for coin above the well-being of their fellow men. Loyalty, wisdom, and religious piety is shown again and again in these stories to lie more securely in the hands of Lamb's common folk.

While female characters occasionally played the familiar role of damsel in distress in these stories, Lamb more typically depicted his women as courageous, independent, and more shrewd than their male counterparts. Their motives and true loyalties, though, remained mysterious to Lamb's male characters, and their unknowable nature is frequently the source of plot tension.

Lamb was never a formula plotter, and his stories often turned upon surprising developments arising from character conflict. The bulk of his Crusader, Asian, and Middle-Eastern stories (as well as the latter stories of Khlit the Cossack) were written in the latter portion of his pulp magazine years, and demonstrate a growing command of prose tools; the more frequent use, for example, of poetic metaphor in his description.

Cossack Tales

By far the largest number of these tales were short stories, novellas, and novels of Cossacks wandering the Asian steppes during the late 16th and early 17th century, all but a half dozen featuring a set of allied characters. Two early books (Kirdy and White Falcon) reprinted the longest of these Cossack adventures, and two later books (The Curved Saber and The Mighty Manslayer) reprinted fourteen of the short stories; the four large Steppes volumes published by The University of Nebraska Press present all of Lamb's Cossack tales in their chronological order.

The most famous of these Cossack characters is Khlit, a greybearded veteran who survives as often by his wiles as his swordarm; he is a featured character in eighteen of the Cossack adventures and appears in a nineteenth. He chooses to wander Asia rather than face forced "Cossack retirement" in a Russian monastery, and launches into an odyssey that takes him to Mongolia, China, and Afghanistan. He comes to befriend and rely upon folk he has been raised to despise, and briefly rises to leadership of a Tartar tribe before he wanders further south. His greatest friend proves to be the swashbuckling Muslim swordsman, Abdul Dost, whom he aids in raising a rebellion against the Moghul emperor in Afghanistan. In later stories Khlit returns as a secondary character, an aged advisor to both his adventurous grandson, Kirdy, and other Cossack heroes featured in separate stories.

Crusader Tales

Unlike Lamb's Cossack stories, only a handful of his Crusader stories are inter-related. Two novelettes feature the young knight, Nial O'Gordon, and three short novels are centered around Sir Hugh of Taranto, who rediscovers the sword of Roland, Durandal. Durandal, published in 1931, reprinted all three novels of Sir Hugh with new linking material. Grant books' Durandal and The Sea of Ravens each reprint a single of these three novels.

While Lamb's Crusaders sometimes battle against their traditional Muslim foes, the majority of these tales feature forays into deeper Asia.

All of Lamb's Crusader stories have been collected in the 2009 Bison volume Swords from the West except for Durandal, The Sea of Ravens, and the forthcoming Rusudan, all from Donald M. Grant co. Related stories with occasional Crusaders are collected in Swords from the Desert (Bison 2009).

Asian and Middle-Eastern Tales

Lamb also wrote a variety of stories featuring or narrated by Muslim, Mongol, or Chinese protagonists, set for the most part during the late 16th and early 17th century. "The Three Palladins" is a story of young Genghis Khan told mostly from the viewpoint of one of his boyhood comrades, a Chinese prince.

Fiction

• Marching Sands (1920)
• The House of the Falcon (1921)
• The Grand Cham (1922)
• White Falcon (1926)
• Durandal (1931)
• Nur Mahal (1932)
• Kirdy (1933)
• Omar Khayyam (1934)
• A Garden to the Eastward (1947)
• The Curved Saber (1964)
• The Mighty Manslayer (1969)

• The Three Palladins (1977)
• Durandal (1981)
• The Sea of the Ravens (1983)
• Wolf of the Steppes (2006)
• Warriors of the Steppes (2006)
• Riders of the Steppes (2007)
• Swords of the Steppes (2007)
• Swords from the West (2009)
• Swords from the Desert (2009)
• Swords from the East (2010)
• Swords from the Sea (2010)

Non-fiction and historical biographies

• Genghis Khan: The Emperor of All Men (1927)
• Tamerlane (1928)
• The Flame of Islam (1930)
• Iron Men and Saints (1930)
• The Crusades (1931)
• The March of the Barbarians (1940)
• Alexander of Macedon: The Journey to World's End (1955)
• The March of Muscovy: Ivan the Terrible and the Growth of the Russian Empire, 1400-1648 (1948)
• The City and the Tsar: Peter the Great and the Move to the West, 1648-1762 (1948)
• The Earth Shakers (1949)

• Suleiman the Magnificent (1951)
• Theodora and the Emperor: The Drama of Justinian (1952)
• Charlemagne: The Legend and the Man (1954)
• Genghis Khan and the Mongol Horde (1954)
• New Found World: How North America Was Discovered and Explored (1955)
• Hannibal: One Man Against Rome (1958)
• Constantinople: Birth of an Empire (1958)
• Chief of the Cossacks(1959)
• Cyrus the Great (1960)
• Babur the Tiger: First of the Great Moguls (1962)