One of the most controversial figures in 19th-century American history, Thaddeus Stevens is best remembered for his role as congressional leader of the radical Republicans and as a chief architect of Reconstruction. Long painted by historians as a vindictive 'dictator of Congress', out to punish the South at the behest of big business and his own ego, Stevens receives a more balanced treatment in Hans L. Trefousse's biography, which portrays him as an impassioned orator and a leader in the struggle against slavery.

Trefousse traces Stevens' career through its major phases, from his days in the Pennsylvania state legislature, when he antagonized Freemasons, slaveholders, and Jacksonian Democrats, to his political involvement during Reconstruction, when he helped author the 14th Amendment and spurred on the passage of the Reconstruction Acts and the impeachment of Andrew Johnson. Throughout, Trefousse explores the motivations for Stevens' lifelong commitment to racial equality, thus furnishing a fuller portrait of the man whose fervent opposition to slavery helped move his more moderate congressional colleagues toward the implementation of egalitarian policies.