Harry Harrison's Deathworld

Deathworld is the first in a series of novels Harry Harrison began in 1960. In it, professional gambler Jason dinAlt who has "psionic" abilities is hired to win a great deal of money for a mysterious and very imposing stranger. When he "breaks the bank" their expertly timed escape gets them off-world just in time. The gambler learns he has helped the dwellers of Pyrrus, otherwise known as "Deathworld" - a planet that appears to be fighting and trying to destroy its inhabitants. Intrigued, he determines to see this world and learn its secrets. He discovers that there are colonists who live outside the embattled city who are not under constant and ever evolving attack from the planet. Jason's efforts to help the city dwellers and re-unite the two planetary groups before they are all destroyed makes for a gripping listen.