Part I Living in Mixed Reality In this Part we start the book with a description of the unevenly mixed realities with whichwearefacedineverydaylife, andwith whichweall dealin ourwork,andin our social and private lives. The difficulties inherent in functioning in these mixed informationalspaces are describedin terms of our inability to form a coherent sense ofthepresencewithinthem.InChap.1,wediscusstheimportanceoffeelingpresent in the world around us, whether this is physical, virtual or, as is now commonplace, a mixture of the two, and introduce the idea of blended reality spaces The problems inherent in existing design approaches in addressing these issues are then examined in detail in Chap. 2.