OA publishing options for scholarly books include:
Some publishers support payment of a book processing charge (BPC) by the author. An OA copy of the book or book chapter(s) is then made available for download from the publisher, e.g. Springer Nature.
Institutionally supported publishers
University or dedicated scholarly presses that publish OA books for free, e.g. ANU Press.
Charles Sturt University Library is a member of Knowledge Unlatched, where Library consortia share the OA publishing costs for selected titles. Selected Knowledge Unlatched titles are listed in Primo Search.
Self-archiving, posting to repository
Some publishers allow authors to self-archive or post book chapters and books in a repository such as CSU Research Output (CRO). Publisher policies vary considerably and it is recommended that authors contact publishers directly.
Further information about developments in OA books is available from AOASG