This book is open access under a CC BY license. Selfies, blogs and lifelogging devices have become important ways in which we understand ourselves. Jill Walker Rettberg analyses these and related genres as three intertwined modes of self-representation: visual, written and quantitative. Rettberg explores topics like the meaning of Instagram filters, smartphone apps that write your diary for you, and the ways in which governments and commercial entities create their own representations of us from the digital traces we leave behind as we go through our lives.