Among the important questions that remain after the success of the standard model, by far the most fundamental would be the understanding of quantum gravity, which is not only of utmost academic interest but also might play the key role in the observational cosmology in an unexpectedly near future.
Although many studies are made on this subject, more often than not, papers on “quantum gravity” actually discuss quantum behavior of matter fields in a (semi-)classical gravity background. Clearly, what is required, however, is a bona fide understanding of the quantization of gravity itself.
In this talk, I wish to make an attempt to
(i) clarify what the essential issues of quantum gravity are,
(ii) survey the present status of our understanding, and
(iii) look for promissing directions of attack,