Nuclear density functional theory. From fundamentals to frontiers

In this summer school organized by Young Nuclear and Particle Physicist Group of Japan (YONUPA), we started from the basic ideas and mathematical fundamentals of density functional theory (DFT) for electron systems, and outlined the relevant challenges and open questions in DFT for nuclear systems. We then moved to some selected applications and frontiers of nuclear DFT. In this proceeding, I will try to recall the lectures in the summer school, with a very personal point of view and selection of literature, which might become an interesting guide for the access of nuclear DTF, but by no means standard lecture notes with complete formulas. (author)