The Stars, Like Dust: Isaac Asimov

Biron Farrell was young and naive, but he was growing up fast. A radiation bomb planted in his dorm room changed him from an innocent student at the University of Earth to a marked man, fleeing desperately from an unknown assassin.
He soon discovers that, many light-years away, his father, the highly respected Rancher of Widemos, has been murdered. Stunned, grief-stricken, and outraged, Biron is determined to uncover the reasons behind his father's death, and becomes entangled in an intricate saga of rebellion, political intrigue, and espionage.
The mystery takes him deep into space where he finds himself in a relentless struggle with the power-mad despots of Tyrann. Now it is not just a case of life or death for Biron, but a question of freedom for the galaxy.