One of HarryT's Omnibus editions:
An omnibus edition of Otis Adelbert Kline's "Venus" series, consisting of the following books:
1. Planet of Peril
2. Prince of Peril
3. Port of Peril
These books have a very similar style of those of Edgar Rice Burroughs' "Barsoom" series; if you enjoy those you should enjoy these too.