Greg Egan is one of the greatest science fiction writers who has ever lived. While his output is not that of a hugely prolific writer he is a double figure novelist and author of over 50 short stories. While excellent at the former, he is brilliant at the latter.
Something that stands out about Egan and his star spanning tales is that they depart from a lot of the usual work in the subgenre, that of wars, thrillers, crime stories, spy stories or the like. His tales are those of intellectual discovery or conflict. The first three listed below are tales of his Amalgam universe. The first where messengers are sent to investigate a rogue self-sustaining planet. The second, Riding the Crocodile has Amalgam citizens who decide there is more to life than immortality in their own neck of the words and decide to explore other regions, particularly one that ignores them. Glory has a pair of researchers travel to a lower technology planet in search of the mathematical insights of an ancient race. Schild's Ladder has far future researchers testing a set of quantum equations, with resultant stellar devastation in need of a solution.
You will find Riding the Crocodile online at the author's website.