Recent progress in magnetism has been made by steadily increasing our understanding of its quantum aspects, as well as by embracing the complexity of magnetic materials with entangled spin, orbital and lattice degrees of freedom. These efforts are revealing new horizons that remained hidden behind this complexity, such as the emergence of low-energy quantum gauge theories that control the collective phenomena of different classes of quantum magnets. Harnessing substantial progress over the last several years, this conference will bring participants together to address outstanding modern challenges of quantum magnetism. These will include the search for real materials with novel topologically-ordered states of matter, the computation and measurement of dynamical and transport properties that can reveal fingerprints of fractionalization and multipolar ordering and the roles of disorder and spin-phonon interaction. We will also include the emergent-electrodynamics induced by topological spin textures, the unusual dynamics of integrable systems, and the revolutionary twist on the quantum 2D magnetism provided by experiments on Moiré systems such as twisted bilayer graphene and transition metal dichalcogenide (TMD) bilayers.