Summer nights in nature are beautiful and mysterious. The full moon shines in the sky, filling the river, meadow, and lakes with a mysterious silvery light. A milky-white fog spreads across the ground like a thin transparent veil. Everything seems unsteady and somehow unreal. And somewhere over the meadow a beautiful song flows, flying upward. Who is hiding there in the mysterious moonlight? On the cover is a fragment of the painting “Dancing Nymphs” by the French artist Paul Chabas (1869-1937).