2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/53260We give a review of some recent developments in the quantisation of $W$-gravity theories. In particular, we discuss the construction of anomaly-free $W_\infty$ and $W_3$ gravities.15 pages (Contribution to the proceedings of the "Strings and Symmetries" meeting, Stony Brook, May 1991.)High Energy Physics - Theorytext