["The Pigman's Legacy" is] a mystery of sorts and also a tale of second chances for both John and Lorraine, not to mention the puzzled beneficiary of their ministrations and an elderly cleaning woman whom they bring into their derring-do. But … it's a rousing adventure yarn too. Mr. Zindel is an old hand at plunging from one episode to the next in such whirlwind fashion that a few implausibilities are concealed along the way. Here he deepens his narrative by alternating narrators chapter-by-chapter between John and Lorraine, which gives us not only John's headlong zest for action and Lorraine's perspective on what's happening but a fine change-of-pace that keeps the tale turning.

Sequels are risky, of course, as they too often merely try to imitate a previously successful formula. But Mr. Zindel is on to something bolder here: Instead of merely tacking it on, he's wrapped his sequel...