Hal Jam is a positive version of the natural instincts that ran amok in Dr. Rat, where the eponymous Dr. Rat exploited the worst aspects of what might be called animalistic inclinations in human beings.

In that novel as well, in contrast to the hideous experiment Dr. Rat performed, a kingdom of spiritual value comprised entirely of animals was part of Kotzwinkle's first extended exploration of a linkage between aspects of humans and animals.

E.T. in both E.T.: The Extra-terrestrial and E.T.: The Book of the Green Planet (1985) is, among many other things, an examination of the outer boundaries of human behavior, while in many of his books for younger readers (but not exclusively younger readers) Kotzwinkle has probed the otherness of creatures not generally thought of as resembling human beings.

And as one of the central themes of his work, Kotzwinkle has...