An overview of the optical characterization of free microparticles and their radiative properties

•The advantages of measuring many observables in light scattering are discussed in view of addressing the technical and theoretical challenges posed by wavelength-scale particles.•We go into the details of what the complex scattering amplitude can reveal about microparticles and why it should be investigated more extensively.•Models that predict the light scattering observables are compared with experimental data, while data inversion is avoided for the sake of clarity and model-independence of the results.