Operation World (OW) is widely regarded as the definitive volume of prayer information about the world and is the recipient of the ECPA Gold Medallion Award for Excellence in Evangelical Christian Literature.
OW has had seven editions published. The most recent is from 2010, which is a complete update of the 21st century edition, released in 2001. The previous edition was published in 1993. The original edition was produced in 1964, from South Africa, and was only 32 pages of basic information about 30 countries.