Polish Quantum Chemistry from Koos to Now, Volume 87 provides a survey of contributions coauthored by Polish scientists working in Poland, and in European and American Universities. Sections in this release include Review: From the Kolos-Wolniewicz calculations to the quantum-electrodynamic treatment of the hydrogen molecule: competition between theory and experiment, Review: How to make symmetry-adapted perturbation theory more accurate, Review: Advanced models of coupled cluster theory for the ground, excited and ionized states, Can orbital basis sets compete with explicitly correlated ones for few-electron systems?, Converging high-level equation-of-motion coupled-cluster energetics with the help of Monte Carlo and selected configuration interaction, and more.Additional chapters cover Coupled cluster downfolding techniques: a review of existing applications in classical and quantum computing for chemical systems, Exploring the attosecond laser-driven electron dynamics in the hydrogen molecule with different real-time time-dependent configuration interaction approaches, Molecular systems in spatial confinement: variation of linear and nonlinear electrical response of molecules in the bond dissociation processes, and much more.- Updates on the latest developments and performance of SAPT- Presents key theory and applications of high precision calculations for few electron systems- Includes discussions on the development and applications of the DFT approach