I think the link below should be able to clearify your query.
"Adobe® Content Server 4
software is a robust server solution that digitally protects PDF and reflowable EPUB eBooks for Adobe Digital Editions software and supported mobile devices, including the Sony® Reader Digital Book. Easy to integrate into existing systems using industry-standard technologies, Content Server 4 allows you to host and manage eBooks on your existing infrastructure. Content Server even supports lending libraries and third-party resellers."
There are also FAQs and product datasheets available too