With examples and clear explanation throughout, this step-by-step approach makes quantum theory of plasmons accessible to readers without specialized training in theory. Jacak uses original research results to offer a fully analytical theory formulation suitable for further development and applications. The theory is focused on the Random Phase Approximation description of plasmons in metallic nano-structures, previously defined for bulk metal. Particular attention is paid to large damping of plasmons in nanostructures including electron scattering and Lorentz friction losses, quantum description of plasmon photovoltaic effect is presented and there is in-depth analysis of plasmon-polariton kinetics in metallic nano-chains. Suitable for students in the field of plasmonics, opto-electronics and photonics, and for researchers active in the field of photo-voltaics, opto-electronics, nano-plasmonics and nano-photonics. Also of help to researchers in soft plasmonics with applications to electro-signalling in neurons.