The Starless World — Gordon Eklund

Captain Kirk encounters Klingons and nocturnal creatures known as Strangers and the sun god himself in a journey of incredible suspense...

Inside the hollow shell of a strange, remote planet Kirk and the Enterprise crew discover a planet within a planet...energized by a white dwarf star...a planet like a lost Eden populated by a race of small, gentle, furred bipeds...a planet falling toward a black hole to spectacular peril and inescapable doom...