Low-temperature paramagnets are spin systems that remain in the disordered (spin-liquid) state down to the lowest temperatures despite the presence of the remarkable exchange spin-spin couplings. Magnetic properties of these systems at low temperatures are due to the collective spin excitations. Excitations spectrum can be controlled by applying magnetic field, which could lead to the unusual phenomenon of the field-induced antiferromagnetic ordering. Magnetic resonance proved to be a sensitive tool to access details of low-energy spin dynamics both in the low-field paramagnetic and high-field ordered phases of low-temperature paramagnet. Magnetic resonance spectroscopy reveals fine structure of the collective excitations' energy spectrum, can follow evolution of the excitations spectrum with the applied magnetic field, reveals details of the excitations' interactions. High energy resolution of magnetic resonance spectroscopy allows to detect low-energy non-Goldstone spin dynamics modes in the high-field ordered phases.