I would like to read an introduction text about how BH can be be formed, with a pure classical point of view (no quantum effects). Is there some dynamic model of BH formation? What are the main conclusions? Is there a characteristic time for the appearance of a finite Scharchild radius? (as seen from far away from the BH) Is there a known grow rate for some given initial mass density? Or do these questions have little sense? Any comment or refences welcome.