SYK model and 2D dilaton gravity have recently attracted considerable attention from the high energy and condensed matter physics community. The success of these models is due to their remarkable properties. Following the original papers, we broadly discuss the properties of these models, including large N diagrammatics, emergence of conformal symmetry in the IR limit, effective action, four-point functions and chaos. Also we briefly review some recent results in the topic. On the one hand, we try to be as specific as possible, i.e. reveal every detail and loophole in the discussion. On the other hand, we expect this review to be suitable even for a reader who is not familiar with these models.