The first published spectrum of an AGN was in 1908. In the 100 years since then we have made significant progress in understanding the phenomenology and physics of AGN. I will begin with a brief history of the development of our understanding, highlighting the major breakthroughs.
I will then recap by describing our present "best" model and the so-called unified scheme. Finally, I will discuss the most important current issues in the field such as; ejection of material from the nucleus and galactic feedback, the association of AGN with starformation and links between black hole growth and galaxy evolution.