Which texts are good for beginners to understand evolution on the genetic scope?
Books on my shelf right now (I'm an evolutionary genetics grad student)...

Entry level:

Evolution - Mark Ridley (not Matt Ridley)

A primer of ecological genetics - Connor &amp; Hartl

Intermediate:

Elements of evolutionary genetics -  Charlesworth &amp; Charlesworth

Advanced:

Principles of Population genetics - Hartl &amp; Clark

Introduction to quantitative genetics - Falconer &amp; Mackay

Further basic/popular-science books include R Dawkins' Selfish Gene/The Extended Phenotype/The Greatest Show on Earth and of course The Origin of Species by Darwin