His major published work, Vitruvius Britannicus, or the British Architect... appeared in three volumes between 1715 and 1725. (Further volumes using the successful title were assembled by Woolfe and Gandon, and published in 1767 and 1771.) Vitruvius Britannicus was the first architectural work to originate in England since John Shute's Elizabethan First Groundes. In the empirical vein, it was not a treatise but basically a catalogue of design, containing engravings of English buildings by Inigo Jones and Sir Christopher Wren, as well as Campbell himself and other prominent architects of the era.
In the introduction that he appended and in the brief descriptions, Campbell belaboured the "excesses" of Baroque style and declared British independence from foreigners while he dedicated the volume to Hanoverian George I. The third volume (1725) has several grand layouts of gardens and parks, with straight allées, for courts and patterned parterres and radiating rides through wooded plantations, in a Baroque manner that was rapidly becoming old-fashioned.
Buildings were shown in plan, section and elevation, but also some were in a bird's-eye perspective. The drawings and designs contained in the book were under way before Campbell was drawn into the speculative scheme. The success of the volumes was instrumental in popularising neo-Palladian Architecture in Great Britain and America during the 18th century. For example, Plate 16 of Vitruvius Britannicus, a rendering of Somerset House in London, was an inspiration for American architect Peter Harrison when he designed the Brick Market in Newport, Rhode Island, in 1761.
Campbell was influenced as a young man by James Smith (ca 1645 - 1731), the pre-eminent Scots architect of his day, and an early neo-Palladian whom Campbell called "the most experienced architect" of Scotland (Vitruvius Britannicus, ii).
The somewhat promotional volume, with its excellently rendered engravings, came at a propitious moment at the beginning of a boom in country house and villa building among the Whig oligarchy. Campbell was quickly taken up by Lord Burlington, who replaced James Gibbs with Campbell at Burlington House in London and set out to place himself at the center of English neo-Palladian architecture. In 1718, Campbell was appointed deputy to the amateur gentleman who had replaced Wren as Surveyor General of the Royal Board of Works, an appointment that Burlington is certain to have pressed, but a short-lived one. When Benton, the new Surveyor was turned out of office, Campbell went with him.