Brian Switek, 27, is a freelance science writer who blogs about the history of science, paleontology and evolution. Look him up atLaelaps ("lay-laps"), scienceblogs.com/laelaps, and Dinosaur Tracking, http://blogs.smith sonianmag.com/dinosaur .

Questions and answers are edited.

Q: Tell us about your new book, "Written in Stone" (Bellevue Literary Press, coming in November.)

Many people would like to believe that the appearance of our species on this planet was an inevitable event caused by a progressive, upward trend in evolution. As I argue in "Written in Stone," however, the vertebrate fossil record tells a different story, one in which unpredictable quirks of history have shaped the evolution of familiar animals such as birds, whales, elephants, horses and even our own species. By looking at famous transitions in the vertebrate fossil record, as well as our changing understanding of them, I hope to provide readers with a deeper understanding of how our species came to be.

Q: Your posts often cover new paleontological finds. What are your favorite kinds of fossils, or species, to write about and why?

I love writing about tyrannosaurs, early whales, fossil carnivores, mastodons and early humans. My blogs allow me to express that enthusiasm to others, and if I didn't have them as outlets I would probably just talk my wife's ear off about the latest fossil finds.

Q: You often write about how earlier scientists understood the fossil record in their time versus how scientists interpret it today. Why this nod to the past?

I'm fascinated by how our understanding of prehistory has changed over the past 200 years. Reading Stephen Jay Gould's essays made me realize how important it is to understand that science is a human endeavor in which our interpretations of the fossil record are almost constantly changing. Writing about the history of science provides context for what we have come to understand about ancient life and reminds us that science thrives on the constant re-examination of what has already been discovered. Who knows? Maybe in 100 years someone will read "Written in Stone" and be just as amazed at how much of what I wrote turned out to be wrong!

T. DeLene Beeland: scwriter.db@gmail.com