The collected works of the outstanding German scientist D. Gilbert include all the main works containing his most outstanding results. The first volume publishes the works of D. Gilbert on the theory of invariants, number theory, algebra, geometry and the foundations of mathematics. Almost all works are first published in Russian. The second volume publishes works on analysis, calculus of variations, integral equations, and physics. In addition, this volume publishes Hilbert's report "Mathematical Problems" and his articles on G. Minkovsky and A. Gurvitz. Almost all works are published in Russian for the first time. The book is intended for mathematicians, physicists and historians of science.