Well, this was quite a hefty collection containing many stories and a couple of novellas, mostly set on Mars or Venus.
In some ways, Leigh Brackett carried on the tradition of swash-buckling adventures in space started by Edgar Rice Burroughs but it's not just more of the same. There is a progression with more complex and imaginative stories and characters. Like Burroughs' John Carter or Carson Napier, she has her enigmatic heroes such as Eric John Stark but her characters are more well-rounded, warts'n'all. Frankly, they are less nauseating
Having said that, not all of the stories worked particularly well for me although the collection seemed to get better as it went on (the stories are in bibliographical order). The novella "Lorelei of the Red Mist" that she co-wrote with Ray Bradbury wasn't that great but "The Sea Kings of Mars" felt like a cross between "Star Wars" and "Raiders of the lost Ark" and was great fun. One of the stories near the end particularly struck me, "The Tweener" as it was very different from the rest being set on earth and more of a psychological horror.
I would say that if like science-fantasy adventures but want something a little more well-rounded than Burroughs, this will be your cup of tea.