For over a century, we’ve accepted the scientific consensus that cancer results from genetic disease due to chromosomal damage in cell nuclei. But what if cancer isn’t a genetic disease after all? What if scientists are chasing a flawed paradigm, and cancer isn’t a disease of damaged DNA but rather of defective metabolism as a result of mitochondrial dysfunction? What if that startling truth could revolutionize our understanding of other diseases as well—and show us a radical new path to optimal health?