It's an important book that should be read by both public people (especially writers) and by private people.
Amazon sells this book for $9.95. With sales tax and free "Prime" second-day delivery, my total price is $10.58. With next-day delivery, the price is $15.57.
As the book's publisher, I earn a royalty of $3.71 per book, lowering my delivered cost to just $6.87 or $11.86.
Naturally, I could order a book directly from CreateSpace. My "direct" price per book is a very reasonable $2.26.
However, unless I can tolerate pokey ten-day delivery, my cost from Amazon is less than from CreateSpace.
The fastest "priority" delivery from CreateSpace takes six days, and costs much more than Amazon's one-day or two-day delivery.