RECENT REVIEWS of books on Qoheleth/Ecclesiastes in the Review of Biblical Literature:

Kamano, Naoto, Cosmology and Character: Qoheleth's Pedagogy from a Rhetorical-Critical Perspective

Miller, Douglas B., Symbol and Rhetoric in Ecclesiastes: The Place of Hebel in Qohelet's Work

Also, from the same source, an extended review by James Barr, with a response from the authors:

Jobes, Karen H and Moises Silva, Invitation to the Septuagint

I haven't read the book, but I do recommend the review as a useful discussion of the current state of Septuagint studies.