Relativistic effects in heavy mesons

We discuss the application of a relativistic potential model to the description of the spectrum and radiative transitions in mesons containing at least one heavy quark (b or c). Although the model has a small number of parameters, it is possible to achieve qualitative agreement with all available experimental data, including those that could not be explained by all previous methods. This demonstrates the importance of taking relativistic effects into account. A remarkable property of the relativistic potential model is that the predictions for meson masses and partial widths of radiative transitions remain finite in the limit of zero light quark mass.