Thurston's 1982 article on three-dimensional manifolds<sup>1</sup> ends with $24$ "open questions": <hr />[![WPT24][1]][1] <br /> $\cdots$ <br /> [![WPT24th][2]][2] <hr /> Two naive questions from an outsider: (1) Have all $24$ now been resolved? (2) If so, were they all resolved in his lifetime? <hr /> > <sup>1</sup>Thurston, William P. "Three dimensional manifolds, Kleinian groups and hyperbolic geometry." *Bull. Amer. Math. Soc*, 6.3 (1982). Also: In *Proc. Sympos. Pure Math*, vol. 39, pp. 87-111. 1983. [Citseer PDF download link](http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.535.7618&rep=rep1&type=pdf). <hr /> ***Answered*** by Ian Agol, Andy Putman, and Igor Rivin. Ian: "Problems 1-18 have been completely answered....Problems 19-24 are more open-ended," and difficult to declare "all settled" (as emphasized by YCor). But, as Andy says, "with the exception of problem 23." Back to Ian: "One can imagine, however, a complete and satisfactory answer eventually to question 23." [1]: https://i.sstatic.net/e9kGo.jpg [2]: https://i.sstatic.net/zZ8NM.jpg