Griggs's first novel follows a familiar formula: two childhood friends are separated by wealth, education, skin tone, and political outlook; one is a militant and one an integrationist. A traumatic incident galvanizes the more moderate friend into action, and the two work together to redress the injustice.
Imperium in Imperio (1899) follows this plotline with a startling twist: the revelation of an African American "empire within an empire," a shadow government complete with a Congress based in Waco, Texas. The light-skinned and more militant Bernard Belgrave who has been hand-picked to serve as president advocates a takeover of the Texas state government, while the dark-skinned Belton Piedmont argues for assimilation and cooperation. Bernard reluctantly has Belton executed as a traitor only after Belton resigns from the Imperium (an act that is tantamount to suicide), leaving the potentially violent and unstable Bernard in control of the Imperium as the novel ends.
The Hindered Hand, written in 1905 as a direct reply to Thomas Dixon's The Leopard's Spots, contains graphic accounts of sexual violence and lynching, and was among the most popular African-American novels of the period.
With a stiff prose style and long rhetorical passages punctuated by melodramatic events, Griggs' novels are not models of "literary" styling. However, for the African-American audiences for which they were written, the novels provided a rare opportunity to read about the political and social issues that preoccupied them, including violence, racism, and the pursuit of political and economic justice.
Although he outsold more famous contemporaries, Griggs remained largely invisible in literary histories of the time. A re-issue of Imperium by the Arno Press in 1969 revived interest in Griggs, and several editions have been published since. Imperium has been embraced as an important addition to the history of utopian literature, western fiction, and African-American literature.