As an inversion-based imaging algorithm, least-squares reverse time migration (LSRTM) refines seismic images toward true-reflectivity earth models. It overcomes the shortcomings of conventional migration algorithms via iterative least-squares inversion to gradually correct migration errors. LSRTM also suppresses side lobes of image wavelets to generate images with high spatial resolution. Recovered weak events and steep dips are enhanced during iterations with balanced illumination. The true-amplitude behavior of LSRTM will greatly benefit quantitative seismic interpretations. LSRTM can be a practical image-domain broadband solution to generate high-resolution images with fine layers as well as accurate complex structures.