This review article by Kravets et al. explores the phenomenon of plasmonic surface lattice resonances (SLRs), which occur when metal nanoparticles are arranged in an ordered array. When light diffracts within the array, it can couple the localized plasmon resonances of individual nanoparticles, leading to a dramatic narrowing of the plasmon resonance width to 1–2 nm. This improvement in quality factors (Q-factors) compared to typical single-particle resonance widths of >80 nm makes SLRs a highly active area of research with potential applications in communications, optoelectronics, photovoltaics, data storage, and biosensing. The article covers the basic physical principles and properties of SLRs, including their width, quality, and singularities of the light phase. It discusses the conditions for excitation of SLRs in different experimental setups, such as in-plane and out-of-plane polarizations of incident light, symmetric and asymmetric optical environments, substrate conductivity, and the presence of active or magnetic media. The review also reviews recent progress in applications of SLRs in various fields, including optical sensing, lasing, and nonlinear effects. Early theoretical studies and experimental observations of SLRs are discussed, highlighting the importance of the coupled dipole approximation and the role of the substrate. The article explains how the dipole sum in the coupled dipole approximation (CDA) can enhance the quality of SLRs compared to localized surface plasmon resonances (LSPRs). It also explores the effect of array period, the use of nanoholes, and the properties of 3D arrays. The experimental section details the first observations of SLRs using ellipsometry and extinction measurements, demonstrating the strong signature of SLRs in reflection and extinction spectra. The article concludes with a discussion of the optimization of SLRs through array period tuning and the potential for enhanced performance in various applications.This review article by Kravets et al. explores the phenomenon of plasmonic surface lattice resonances (SLRs), which occur when metal nanoparticles are arranged in an ordered array. When light diffracts within the array, it can couple the localized plasmon resonances of individual nanoparticles, leading to a dramatic narrowing of the plasmon resonance width to 1–2 nm. This improvement in quality factors (Q-factors) compared to typical single-particle resonance widths of >80 nm makes SLRs a highly active area of research with potential applications in communications, optoelectronics, photovoltaics, data storage, and biosensing. The article covers the basic physical principles and properties of SLRs, including their width, quality, and singularities of the light phase. It discusses the conditions for excitation of SLRs in different experimental setups, such as in-plane and out-of-plane polarizations of incident light, symmetric and asymmetric optical environments, substrate conductivity, and the presence of active or magnetic media. The review also reviews recent progress in applications of SLRs in various fields, including optical sensing, lasing, and nonlinear effects. Early theoretical studies and experimental observations of SLRs are discussed, highlighting the importance of the coupled dipole approximation and the role of the substrate. The article explains how the dipole sum in the coupled dipole approximation (CDA) can enhance the quality of SLRs compared to localized surface plasmon resonances (LSPRs). It also explores the effect of array period, the use of nanoholes, and the properties of 3D arrays. The experimental section details the first observations of SLRs using ellipsometry and extinction measurements, demonstrating the strong signature of SLRs in reflection and extinction spectra. The article concludes with a discussion of the optimization of SLRs through array period tuning and the potential for enhanced performance in various applications.