The last in my current sequence of Heinlein books but not my last!
The picture on the cover of this version describes something that happened in the story and which stuck with me since I first read the book as a youth. There are primal fears in that image!
I think that one of the enduring attractions of Heinlein is his ability to capture the imagination of the reader and to influence how the reader thinks about things - the renown Heinlein philosophy of life. There is a great deal to like about this book and I recommend it to you.