Links are listed for information not endorsement.
B British Library – Timelines: Sources from History
C Catalogue of Digitized Medieval Manuscripts | The Center for the Study of Books and Media (Princeton) | The Centre for the History of the Book (Edinburgh) | Centre for the Study of the Book (Oxford) | The Conveyor (Bodleian Libraries blog)
E Early Modern Paleography (Yale)
H HoBo [formerly History of the Book at Oxford]
I Incunabula Project blog (Cambridge)
M Le manuscrit médiéval / The Medieval Manuscript
P Paleographical Commons (Flickr)
S The Society for the History of Authorship, Reading and Publishing (SHARP)
Y Yale Law Library – Rare Books Blog