From the author of the national bestseller Dead Man Walking comes a brave and fiercely argued new book that tests the moral edge of the debate on capital punishment: What if we're executing innocent men? Two cases in point are Dobie Gillis Williams, an indigent black man with an IQ of 65, and Joseph Roger O'Dell. Both were convicted of murder on flimsy evidence (O'Dell's principal accuser was a jailhouse informant who later recanted his testimony)...