"What Evolution Is" by Ernst Mayr is a good old school non-controversial introduction imo.
If you are going to read Dawkins or Gould you should realize that they have a lot of disagreements with regard to some of the specifics of evolution, e.g., unit of selection, relative roles of selection and chance, etc.
So after you read a book by Dawkins and/or Gould and have a grasp of the subject I'd put "Dawkins vs. Gould: Survival of the Fittest" on your reading list to understand their differing viewpoints.