Deathworld (version 2)

Pyrrus is trying to kill them all. That's not metaphor. The planet itself has declared war on its human colonists: every animal carries deadly poison, every plant is a trap, and the gravity crushes you with twice Earth's weight. The settlers didn't just survive this hellscape. They evolved into something harder, faster, deadlier. A three-year-old carries a loaded gun because not carrying one means being dead before sunset. Enter Jason dinAlt, an interplanetary gambler who talks his way onto the first shuttle bound for Pyrrus and immediately realizes he's made the worst bet of his life. The planet that was once habitable has become a killing ground, and nobody knows why. Now the galaxy's most charming degenerate has three choices: figure out what's turned Pyrrus hostile, die trying, or watch humanity's toughest colonists get wiped out anyway. Deathworld is propulsive adventure SF at its finest. Harrison writes with sharp wit and relentless pacing, wrapping a genuinely clever ecological mystery inside wall-to-wall action. It's the kind of book that makes you check over your shoulder while reading on a seemingly safe planet called Earth.