I'm sorry I've taken so long on this one. I have a horribly lame excuse: The thing is that I found Cosmicomics so astonishingly original, insightful, and entertaining that I'm not sure I can write a concise description that will do it justice. To get the general idea, have a look at the posts of the other Nonbelieving Literati: from No More Hornets, An Apostate's Chapel, Right to Think, Spanish Inquisitor, Tales of an Ordinary Girl, and The Greenbelt. All I'd like to add is that these tales are fundamentally human yet encourage the reader to contemplate the most fantastic physical possibilities and impossibilities.
My favorite passage from this book is one that describes a relatively mudane insight (relative to some of the stuff in this book), but which is one of my personal favorite topics: comparing a character's self-image with the way s/he is perceived by others. These are the words of a dinosaur living incognito among the "New Ones" who came after the dinosaurs:
The stories were terrifying. The listeners, pale, occasionally bursting out with cries of fear, hung on the lips of the storyteller, whose voice betrayed an equally profound emotion. Soon it was clear to me that all of them already knew those stories (even though the repertory was very plentiful), but when they heard them, their fear was renewed every time. The Dinosaurs were portrayed as so many monsters, described with a wealth of details that would never have helped anyone recognize them, and depicted as intent only on harming the New Ones, as if the New Ones had been from the very beginning the Earth's most important inhabitants and we had nothing better to do than run after them from morning till night. For myself, when I thought about us dinosaurs, I returned in memory to a long series of hardships, death agonies, mourning; the stories that the New Ones told about us were so remote from my experience that they should have left me indifferent, as if they referred to outsiders, strangers. And yet, as I listened, I realized I had never thought about how we appeared to others, and that, among all that nonsense, those tales, here and there, from the narrators' point of view, had hit on the truth. In my mind their stories of terrors we inflicted became confused with my memories of terror undergone: the more I learned how we had made others tremble, the more I trembled myself.