Michael Gundlach, a developer in the US, created AdBlock in 2009. Since then, other people have liked AdBlock so much that they've contributed code or time to help the project.

Here's a little more about Michael and his original work with AdBlock:

https://sleeplessgeek.blogspot.com/2010/02/q-with-michael-gundlach-creator-of.html

https://blog.flattr.net/2011/11/michael-gundlach-the-man-who-blocked-100-billion-ads/