The following files are the official charts that came with Civ4: download the [url=http://www.civfanatics.net/downloads/civ4/reference/CIV4%20TECHTREE%20FRONT%20ENG%20Lo%20Res.pdf]front[/url] and the [url=http://www.civfanatics.net/downloads/civ4/reference/CIV4%20TECHTREE%20BACK%20ENG%20Lo%20Res.pdf]back[/url]. (PDF files, 844 KB and 2.5 MB respectively.)