History Of Photoshop

20 years of Photoshop

http://www.webdesignerdepot.com/2010/02/20-years-of-adobe-photoshop/

Adobe Photoshop Version History

https://en.wikipedia.org/wiki/Adobe_Photoshop_version_history

I have been researching into photoshop - I wanted to see how photoshop has developed over time, what additions have been made to each version, so that it has become the user-friendly application that we use today. 

Also how it's simplified processes like photo manipulation and typesetting/font selection, that in the past would've been very laborious.