The WCC Library holds about 100,000 volumes and 900 specialized periodicals, some more than a
century old. This includes a unique and comprehensive collection on ecumenism and the history of the ecumenical movement since the early 20th century and collections in specialized areas, such as biblical hermeneutics, social ethics, missiology, contextual theology, and interfaith dialogue.
For reasons of limited space in Bossey, minor collections on church history, Christian denominations, doctrinal theology, and the journals are housed in the WCC Archives, located at the Ecumenical Centre, Geneva.The holdings of WCC Archives may be consulted by appointment.
The WCC Library also holds a Rare Books collection, comprising older publications from the 17th to 19th century, in addition to special collections, named after their donors, e.g. the Philip de Vargas collection on Chinese Christianity in the early 20th century, and a part of Jacques Waardenburg's personal library and documentation on Christian-Muslim dialogue within the European context, and the institutional deposit collection of all WCC publications. All these special collections are kept at the Ecumenical Center, Geneva, under the custody of WCC Archives.
Most of the WCC Library collections are referenced in the and may be consulted on site in Bossey Library or WCC Archives. However, publications catalogued before 1986, the date of the computerization of the library system, about 30.000 titles, are referenced in a manual paper catalogue which may be consulted in WCC Archives. ue
A recent initiative was the launch in September 2011 of GlobeTheoLib, the "Global digital library on theology and ecumenism", a joint project of Globethics.net and the WCC through its programme of Ecumenical Theological Education, in collaboration with WCC Library. GlobeTheoLib may be used free of charge and by anyone interested in the field.