A world of endless sky, with no land, no gravity: this is Virga. Beginning in the seminal science fiction novel "Sun of Suns," the saga of this striking world has introduced us to the people of stubborn pride and resilience who have made Virga their home; but also, always lurking beyond the walls of the world, to the mysterious threat known only as Artificial Nature. In "The Sunless Countries," history tutor Leal Hieronyma Maspeth became the first...