A very good book about what you need to understand, need to do to implement DNSSEC. As usual with @mwl@io.mwl.io, you'll be taken by the hand, and you'll understand how/why the protocol works. You'll get the why's and how to manage it, but it won't delve into the technical details (eg do this, those lines etc ... That you'd find in a regular HOW-TO). If I were to manage DNSEC outside my current registrar, I'd read that book again.