According to the modern version of Darwin's theory, DNA contains a program for embryo development that is passed down from generation to generation; the program is implemented by proteins encoded by the DNA, and accidental DNA mutations introduce changes in those proteins that natural selection then shapes into new species, organs and body plans. When scientists discovered forty years ago that about 98% of our DNA does not encode proteins, the non-protein-coding portion was labeled "junk" and attributed to molecular accidents that have accumulated in the course of evolution.

Recent books by Richard Dawkins, Francis Collins and others have used this "junk DNA" as evidence for Darwinian evolution and evidence against intelligent design (since an intelligent designer would presumably not have filled our genome with so much garbage). But recent genome evidence shows that much of our non-protein-coding DNA performs essential biological functions.

The Myth of Junk DNA is written for a general audience by biologist Jonathan Wells, author of Icons of Evolution. Citing some of the abundant evidence from recent genome projects, the book shows that "junk DNA" is not science, but myth.