>> daniel halperin and i had thousands of conversations over many years. we've would say there is something for everybody to pay. on the left, if you believe it could be told with the discussion of poverty, poor health care and remedy is testing and condoms, that is not the whole story. of the right, believing about abstinence marital values, not to the whole story. aids is the most politicized epidemic of the growth having to do with the age that we live in. people yell at each other on tv or over facebook. with illegal drug use, the death, the sad truth is not curable and many years, not treatable, the stakes are very high. we've right by the time the epidemic is discovered it plans in the middle of culture for common gay people are fighting for their rights and recognition , that intensity made it hard for a consistently cool headed look at the fax at the time. we hope the book delivers on the promise that the only thing that matters is to move the story to get right so the response is better. >> host: i am very familiar with daniel and now your work. y

craig timberg and daniel halperin, welcome. >> thank you for having us. >> suarez: the book is about a great many things but one of the conclusions that's gotten a lot of attention is the responsibility of colonialism for helping aids break out of the deepest rain forests into the rest of the world. how does that happen? >> well, the virus that became h.i.v. was infected a community of chimpanzees for hundreds of years, probably thousands of years and scientists now theorize it made its way into the human population several times over the centuries as humans caught chimps, butchered them, the blood passed through a cut. what's crucial about the moment that leads to the aids epidemic is that at that exact moment there are new intrusions of steam ships and porter paths as humans move into the remote places where the chimpanzees lived and it's at that moment when h.i.v. becomes a human epidemic, starts moving down the rivers and into the birthplace of the epidemic in central africa. >> even to this day there are small strains of h.i.v. virus that exist, for example, in cameroon there ar