yep, definitely an affiliate link. in previous posts atwood would disclose the affiliate links in the post (not sure why he didn't do so this time). amazon usually pays 4% on referrals (in this case 42$), so depending on the loyalty of his readership this "review" might be moderately lucrative.
In case anyone doesn't know, he's been one of the most popular Programmer bloggers for many years. He also started StackOverflow with Joel Spolsky (another very popular blogger). So his posts tend to be noticed.
