From De Gruyter:
De Gruyter is providing sponsorship for the Directory of Open Access Books to celebrate the launch of the De Gruyter Open Access Book Library on degruyter.com which is intended to draw attention to the growing number – and growing importance – of open access books. Not only does the Library contain all of De Gruyter’s open access books, it also contains those of publishing partners.
Of the almost 900 titles [in the De Gruyter OA Library], approximately half are De Gruyter titles, with the other half being supplied by publishing partners, but available on degruyter.com.
Direct to De Gruyter’s Open Access Collection
Direct to Directory of Open Access Books