[quote][b]Posted by:[/b] monkDAN we do know why they disappeared, they were loosing to the flood so they fired the rings but didn't get to the shield worlds. [/quote] It is never said that they didn't get to the shield worlds. They truly disapeared. Most of their race was killed by the Halos but many did escape and the upcoming Forerunner books starting in January are supposed to explain what happened to the Forerunners.