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