It is generally accepted that Sir Isaac Newton published eight major works in his lifetime. Additionally, four major works were published posthumously. This count is open to scholarly debate, as, at the time of writing, there were multiple variations and drafts available.
The Newton Project includes the most complete listing of all of Newton's works, letters, notebooks, drafts and fragments. As such, it has 250 entries. A number of these are drafts of his main works. The most reliable count remains at a dozen major works, which span topics such as mathematics, optics, gravitation, alchemy, translation and biblical analysis and interpretation.