@Oddthinking Yup, it was Karen Brodkin Sacks, and here's the book, "Race", on Amazon.com. It looks like I misstated that she wrote the book, though - apparently the book itself is a compilation of various authors' papers, and she was just the author of the cited chapter.
If anyone else stumbles on this later, here's a PDF of "How did Jews Become White Folks?. Interestingly enough, the first page of the PDF also has a disclaimer from the Catalyst Project (which is hosting the PDF) disclaiming that this paper/chapter has "some limitations and shortcomings".
Discussion on question by Andrew Grim…
Discussion on question by Andrew Grim…