Henrietta Lacks, a poor Southern tobacco farmer, was buried in an unmarked grave 60 years ago. Yet her cells --- taken without her knowledge --- became one of the most important tools in medical research. Known to science as HeLa, the first "immortal" human cells grown in culture are still alive today, and have been bought and sold by the millions. Rebecca Skloot takes us on an extraordinary journey from the "colored" ward of Johns Hopkins Hospital in the 1950s to East Baltimore today, where Henrietta's family struggles with her legacy.