Much of the pleasure we take from birds is tied to the science that envelops these amazing creatures. Science explains flight and song and navigation. It also explains feathers, the one thing that defines birds most specifically.

Feathers are essential to our perception of birds. But with or without birds, feathers have a most interesting life of their own. Author Thor Hansen has given us the story of feathers in a fascinating book entitled "Feathers: the Evolution of a Natural Miracle."

My list begins with the first feathers. They were worn by a creature from the Mesozoic era, a reptile-cum-bird that left us only rare impressions of its singular creation. Archaeopteryx is its name. It appeared like magic when a piece of slate was split in an English quarry.

One of the quarrymen smuggled this fossil home, incidentally using it as payment to a doctor for treatment of a lung condition, a doctor with an interest in fossils. That was in 1861. It was, as author Hanson says, "the first full specimen of … an ancient animal with the skeleton of a reptile and the feathers of a bird." It went on to become one of the most famous and most studied fossils ever.

This ancient animal's Latin name is more than descriptive. It's beautiful and poetic, uncommon things for scientific names: Archaeopteryx – "ancient wing written in stone."

Hanson explores and explains as he examines a deep pile of feathers.

Why do birds lose feathers in a process called molt? Why pay the high-energy price for a new set of what you already have? For the same reason you replace tires or windshield wipers on your car, Hanson says: things wear out. Molting also is the most reliable way birds have to keep lice somewhat under control.

Feathers keep birds warm. They also help keep birds cool. Hanson placed a dead flicker in the sun. In a few minutes the outside temperature of the bird was 102 degrees Fahrenheit. A thermometer slipped beneath the feathers registered only 87 degrees.

Throughout the book Hanson weaves history and myth into explanation and knowledge, a recipe for a most readable effort.

Hanson is a conservation biologist who has worked in Africa and Central America. His first book, "The Impenetrable Forest: My Gorilla Years in Uganda," won the 2008 USA Book News Award for nature writing. The book has been published by Basic Books. It is hard bound with a handsome jacket, 336 pages, a few illustrations, and an index. Price is $25.99.

Feathers from a phalarope, a species of shorebird.