The Selfish Gene by Richard Dawkins
The Meme Machine by Susan Blackmore
Virus of the Mind: The New Science of the Meme by Richard Brodie
Contagious Metaphor by Peta Mitchell
Gödel, Escher, Bach: An Eternal Golden Braid by Douglas R. Hofstadter
These books are a good introduction, and if you are serious about memetics, you should read all of them.
Other interesting sources:
http://eumetics.com/
https://www.laetusinpraesens.org/docs00s/singmem.php