The goal of this major undertaking is to support and enhance the interactions between mathematics and physics by making full use of the modern information technologies. Indeed, the 20th century was full of dramatic discoveries in each domain. And the important advances of that century in Mathematical Physics demonstrate clearly that physics is much closer to deep problems in mathematics than one could imagine by studying textbooks in our universities, and that physical ideas and concepts are often seminal in mathematics. The Modern Encyclopedia of Mathematical Physics (MEMPhys) is a truly 21st century scientific encyclopedia, emphasizing mathematical physics as opposed to mathematics on one side and physics on the other. The central idea is to create a modern version of Maimonides’ Guide for the Perplexed, albeit limited to this multidisciplinary field. Indeed nowadays, increasingly so, the problem (especially in science) is not so much the existence or availability of information,...