By R.F. KuangFantasy/Harper Voyager/Paperback/560 pages/$35.92 Academia can be hell, as anyone who has slogged through the desert of a doctorate only to tumble into the fiery pit of the job market will tell you. American author R.F. Kuang takes this literally in her sixth novel, Katabasis, in which two graduate students go to hell to retrieve their thesis adviser’s soul. Kuang, who made her name with the fantasy trilogy The Poppy War (2018 to 2020), is one of publishing’s darlings.