Science fiction: Adventure, Horror, Mystery Classics Best Seller's for 99 Cents The Dual World (adventure, fantasy, romantic, action, fiction, science fiction, amazing , western, thriller, crime novel)

A decent story recounting adventures on the lost continent of Venus where a strange duality exists. However it is probably more noteworthy from the aspect that one of the main characters is female captain of a ship. Not something that was seen often in fiction from the 1930s. And it's a tight ship she runs, too.