Jeff Singer is President and CEO of Health Care of the Homeless. This interview was recorded in his office in January 2008. There is a common assumption in our society that homelessness is caused by personal irresponsibility, often attributed to mental illness or substance abuse. Do you agree with this view, or is homelessness produced by deeper structural and economic conditions? Well first, it’s curious to think that mental illness or substance abuse have anything to do with personal responsibility.