Hard to imagine I neglected to mention this before now, but two weeks ago I published and released my first book, «postmaster@YOUR_DOMAIN_HERE», at the M3AAWG Montreal Night Out. The book is essentially a primer and digest of topics of interest to new email administrators; a collection of topics they should be aware of when managing their email systems.
The contents are freely available online to new and experienced postmasters to consult and contribute. Visit The Postmaster Administration Wiki.
Update: The book is available from Amazon.