The Ultimate Critical Edition

Professor Menahem Kahana is the unrivalled expert in Tannaitic Midrash (Midrash Halakhah). Over the past decade he has published two major books. The first was a partial and comparative edition of the two Mekhiltot on Exodus, focusing on the Aggadic section about Amalek. The second was an edition of Sifre Zuta on Deuteronomy - a midrash that was so lost we didn't even know it existed until Kahana found it.
Kahana's doctorate was a prolegomenon to Sifre Numbers. Now, almost thirty years later, the groundwork he laid there is beginning to come to fruition. The first volume of his critical edition of Sifre Numbers has been published by Magnes. It includes an introduction, and the full critical apparatus for the first 106 pericopes of the midrash. It also has a more minimal edition of the remainder of the midrash (a simple transcription of the Vatican MS). Two more volumes are supposed to appear soon, with his exhaustive commentary on the first part of the midrash. The commentary and the full edition of the last part is still in the works. The TOC and preface are online.
I haven't seen the book yet. But I've taken enough courses with Kahana, and read enough of his published work, to know that the standards of this edition are extremely high. I'm not sure I'll be able to find room on my shelf for all these volumes of a midrash that until now took up only a couple of centimeters. But I look forward to seeing the complete edition in print.