I received in the mail today the latest installment of my Planet Stories subscription, The Swordsman of Mars by Otis Adalbert Kline (Writers used to have such terrific names, didn't they?) Kline is probably not very well known to many people today, except perhaps as Robert E. Howard's literary agent from 1933 until REH's death three years later. Kline continued to act in that capacity afterward, helping to get Howard's manuscripts published posthumously, including the planetary romance, Almuric (also available from Paizo).
Prior to this, though, Kline had penned many pulp fantasies himself, including the Martian adventures of Harry Thorne. This is the first complete edition of the stories to have appeared since the 1930s, which alone is good enough reason to read them. That they're also excellent tales that compare very favorably with those of Burroughs only adds to their attraction.
Once again, my hats off to Paizo and Planet Stories. Frankly, I can't think of a more exciting series of books being published anywhere today.