Whitehead torsion of inertial h-cobordisms

We study the Whitehead torsion of inertial h-cobordisms, continuing an investigation started in [12]. Of particular interest is a nested sequence of subsets of the Whitehead group, and a number of examples are given to show that these subsets are all different in general. The main new results are Theorem 2.5, Theorem 2.6, Theorem 2.7. Proposition 5.2 is a partial correction to [12, Lemma 8.1].