Since 2009 is the International Year of Astronomy, here is something I thought I'd pull out of my personal archive. It is a dissertation I wrote for the third year of my MPhys, reviewing achievements in cosmology between 1916 and 1999. I invite everyone who reads this to add any achievements in cosmology since then in the comments! If I get enough interest in this post, I'll consider writing an updated version. In the meantime, you can also find this dissertation at Scribd.com where you can read More