Thanks to a posting on Polymeros kai polytropos, I became aware of a new book published on Philo and the letter to Hebrews:
Stefan Nordgaard Svendsen.
Allegory Transformed: The Appropriation of Philonic Hermeneutics in the Letter to the Hebrews. Wissenschaftliche Untersuchungen zum Neuen Testament, Reihe 2. Mohr Siebeck, 2009.
The publishers own presentaation of the book runs thus: “Scholars have long discussed whether the writer of Hebrews might have been influenced by Philo of Alexandria. In spite of any disagreement, though, academics have almost universally concurred that even if bits and pieces of Philo’s thinking should have filtered through to Hebrews, Philo and Hebrews certainly differed with respect to their biblical hermeneutics. Philo, the philosopher, read the Old Testament allegorically, whereas the Christian author of Hebrews committed himself only to typological exegesis. Stefan Nordgaard Svendsen challenges this consensus, arguing that the writer of Hebrews not only employed Philo’s allegorical method, but also developed his own readings of Scripture through critical rereadings of Philo’s exegetical results. This study sheds new light on the intellectual framework of Hebrews as well as on the letter’s purpose and rhetorical strategies.”