This book, one of the few in the domestic and world scientific literature, provides information on mathematical concepts, terms and designations. The reader will know who introduced the concept, definition and term and when; as it was called at its first appearance; when the modern term originated and by whom it was proposed; what it means in accurate translation into Russian; to whom the symbol belongs (if any). Information is given in alphabetical order. The guide will be useful to a wide range of readers - mathematicians and historians of science. Scientists, teachers, graduate students, students, high school students and just lovers of mathematics will find a lot of interesting things in it.