De Forest's writings encompass nearly every genre, from history to novels. His most famous novel, Miss Ravenel's Conversion from Secession to Loyalty, was published in 1867. The title sums up the book fairly well. He also wrote poetry, including "En Voyage":
I stood in Venice, on the Bridge of Tears,
And sighed to see the spectres thronging through;
But they replied, "You are the captive, you!
We have been free as air these many years."
I watched the billows beat the Adrian shore;
Each tossed exultingly, then ceased to be;
And one of them was you, and one was me:
But Ocean lived and thundered as before.
The Coliseum! There at Caesar's feet,
The gladiator bowed his pale farewell;
But pausing there, I mused of Heaven and Hell,
And worlds dismissed to triumph or defeat.
While in the Pantheon I knelt to pray,
With thoughts of Jove and Jesus much perplext,
A broken Hermes scoffed, "What credence next?"
And haloed saints lamented, "Who can say?"
To find the Truth, the Truth that cannot die,
I wandered darkling, wandered everywhere,
Until a statue, through the Grecian air,
All beautiful, responded, "Here am I."