<p>Laser-induced breakdown spectroscopy (LIBS) is an atomic optical-emission technique with the attractive characteristics of performing spectroscopic analysis ‘at a distance’, on an untreated sample and on very short timescales. Further advantages are high spatial resolution and microdestructivity; also LIBS can be performed on samples in the solid, liquid or gaseous state. All of these advantages arise from the use of a pulsed laser that both samples and excites the material under study, through the mechanism of laser ablation. However, analysis of the resulting optical-emission spectra is complex, and is probably the main reason that LIBS is only slowly being adopted as a viable analytical technique. Nevertheless, LIBS provides excellent elemental imaging, and is finding applications across a range of fields, including in industrial processes, environmental and biomedical analyses, geology and mining, and in cultural heritage. This Primer discusses the key points to consider before, during and after a LIBS measurement, to optimize the experimental conditions, acquire and analyse representative spectra, and properly communicate the results. The most promising current applications of LIBS are described, as are future directions for the development of LIBS that could make it an effective competitor to mainstream analytical techniques.</p>