Afortunadamente pude conseguirlo en formato djvu, pero lo convertí a pdf para que esté más accesible a todos los que quieran leerlo sin necesidad de programas especiales.
Aquí les va el enlace de descarga a este gran libro del biólogo Richard Dawkins.
The main metaphorical treatment is of a geographical landscape, upon which evolution can only ascend in a gradual way, not being able to climb cliffs (this is known as an adaptive landscape). In the book he gives various ideas about a seemingly complex mechanism coming about from many different gradual steps, that were previously unseen.
The book grew out of the annual Royal Institution Christmas Lectures which Dawkins delivered in 1991 (see Growing Up in the Universe). It is illustrated by Dawkins' wife Lalla Ward; and is dedicated to Robert Winston, "a good doctor and a good man".