"With stocks you have to worry about the market," he says. "With debt I just have to understand the contract. If my analysis is right, I'll make money." By "contract," he means documents that spell out debt holders' rights. It also helps to own enough of a sickly company's debt to have a say in any reorganization.
While I haven't read Whitman's latest books, I can heartily recommend his first two--The Agressive Conservative Investor and Value Investing: A Balanced Approach.
In each of these, you will see Whitman's strategy explained clearly. You will see that he focuses primarily on what is as opposed to what will be--and as his record attests he has proven to be very good at doing this.
As the Forbes article shows, Whitman has had a tough three years, but this is where he should be expected to excel--given his past record, his strategy, and the type of deals being offered now.