The beetle in the anthill

"In this chapter of Arkady and Boris Strugatsky's ever-deepening saga of the Noon Universe, Maxim Kammerer, once an intrepid young space explorer, is now an investigator with COMCON-2, the covert agency in charge of countering threats to the homeworld. He is tasked with tracking Lev Abalkin, a "progressor" tasked with guiding the development of civilizations on alien worlds, who has returned to Earth after a routine mission went tragically wrong. Do the secrets of Abalkin's past pose a grave danger to humanity-or is he an innocent caught up in a deadly misunderstanding?"--