The Perseus Book Group is expanding its agreement with Oyster, the e-book subscription service, and will make an additional 4,000 titles available to Oyster subscribers. The titles will be released on an ongoing basis starting today and will include all Perseus imprints.

Among the titles now available to subscribers are Dirty Wars by Jeremy Scahill, The Design of Everyday Things by Don Norman and The Garden of Evening Mists by Tan Twan Eng.

The Perseus Book Group launched a pilot program with 100 titles with Oyster in December with plans to increase the number of titles after testing the service. The e-book subscription service launched in September of 2013 and offers unlimited access to about 100,000 titles for $9.99 a month.