Eighty-two years after the first edition of Paradise Lost, Thomas Newton completed work on the first definitive edition of Milton's epic poem. This text arose directly from the controversy surrounding Richard Bentley's 1732 edition.

Newton used the last authoritative edition (1674) published at the time of Milton's death as his copy-text and carefully collated the text with the first edition of 1667. He also had access to all other major editions published prior to 1749 and used them as necessary to verify and correct perpetuated errors. His notes synthesized the work of many different scholars and became the standard for scholarly editions for nearly 150 years.

To accompany the newly refined text, the Tonsons contracted with artist Francis Hayman to design new illustrations for the 1749 edition. Hayman was a prominent English decorative painter and had recently completed thirty-six illustrations for an edition of Shakespeare's works.