Publishing in Open Access increases usage and has no effect on book sales

"Open Access publishing has no negative effect on book sales, and increases online usage and discovery considerably. This is one of the conclusions of OAPEN-NL, a project exploring Open Access monograph publishing in the Netherlands. OAPEN-NL’s final report, published yesterday, gives recommendations for research funders, libraries, publishers and authors....The publisher’s fear that book sales would decline if publications would be available in Open Access, was unfounded. However, online usage of books in Open Access increased considerably as did online discovery of these books. Although online usage increased, this did not (yet) lead to an increase of citations in the research timeframe."