The biennial ICSLS conferences review the most recent theoretical and experimental advances in both fundamental and applied work dealing with the formation of spectral line profiles, the underlying physical processes, and the use of line shape analysis for diagnostic applications. Spectral line shapes and shifts are affected by the interactions between atoms, molecules, ions, electrons and photons. Therefore, their measurement and interpretation provides information on the physical properties of all kinds of material systems, from astrophysical and nuclear-fusion plasmas to superfluid helium droplets. Topics discussed in these proceedings include dense plasmas, hydrogen plasma broadening, asymmetry, non-hydrogenic line profiles, plasma-diagnostic and other applications, general theory, high-resolution spectroscopy, alkali-doped helium clusters, molecules and atoms, optical collisions, collision-induced effects, and related topics.