Il Penseroso (The Serious Man) is a vision of poetic melancholy by John Milton, first found in the 1645/1646 quarto of verses The Poems of Mr. John Milton, both English and Latin, published by Humphrey Moseley. It was presented as a companion piece to L'Allegro, a vision of poetic . The speaker of this reflective ode dispels "vain deluding Joys" from his mind in a ten-line prelude, before invoking "divinest Melancholy" to inspire his future verses. The melancholic mood is idealised by the speaker as a means by which to "attain / To something like prophetic strain," and for the central action of Il Penseroso – which, like L'Allegro, proceeds in couplets of iambic tetrameter – the speaker speculates about the poetic inspiration that would transpire if the imagined goddess of Melancholy he invokes were his Muse. The highly digressive style Milton employs in L'Allegro and Il Penseroso dually precludes any summary of the poems' dramatic action as it renders them interpretively ambiguous to critics. However, it can surely be said that the vision of poetic inspiration offered by the speaker of Il Penseroso is an allegorical exploration of a contemplative paradigm of poetic genre.
It is uncertain when L'Allegro and Il Penseroso were composed, as they do not appear in Milton's Trinity College manuscript of poetry. However, the settings found in the poem suggest that they were possibly composed ca. 1631 shortly after Milton left Cambridge in 1629.
As prelude to his invocation of Melancholy, the speaker dismisses joy from his imagination. Its rhythm of alternate lines of iambic trimeter and iambic pentameter is identical to that of the first 10 lines of L'Allegro:
The speaker invokes a Melancholy goddess, veiled in black: