The Spirit of the Age was a collection of short essays, or more accurately character sketches, in which Hazlitt, a prominent literary critic, examined twenty-five of the most important thinkers, poets, politicians, and social activists of his time. Hazlitt is revealed through his critiques to be sympathetic, with some reservations, with the English left. He is distrustful of the English nobility, charging that Lord Byron's "chief error" is that he is "that anomoly...a noble Poet." He criticized many of his contemporaries who sought to use the thought of Thomas Malthus to justify depriving the poor of any assistance whatsoever. From a literary standpoint, he was most effusive in his praise for people like Wordsworth, who focused more on his inner self than on abstract ideals:
He takes the simplest elements of nature and of the human mind, the mere abstract conditions inseperable from our being, and tries to compound a new system of poetry from them; and has perhaps succeeded as well as any could.
The concern with simplicity and authenticity is pervasive in Hazlitt's literary criticism. Overall, however, Hazlitt was interested in portraying to his readers the "spirit of the age," as the book's title suggests. He wanted to provide a panoramic view of important writers and intellectuals of his time.