This lecture course is regarded as an addition to the regular course of Dynamical Systems. Although I deliberately limit myself to one-dimensional dynamics, some principal concepts and proofs of the modern theory of Dynamical systems are introduced. In particular, the course includes - a brief introduction to Ergodic Theory, - continuous mappings of a circle, - continuous and smooth mappings of the segment, - some facts of the Bifurcation Theory, - a brief introduction to Interval Exchange Maps. If we have enough time some aspects of 1D Complex Dynamics can also be considered. The syllabus given below is flexible. Some parts of this course can be omitted provided all the students know them already (this mainly concerns the first part of the course). Meanwhile, the most sophisticated part of the course (presumably, the Complex Dynamics) can be reduced, if necessary. C. Syllabus, the main content, and the corresponding period distribution (a total of 48 hours, every period of 50 minutes each).