From the back of the book:
"The classified files of the covert government agency the Department of Extranormal Operations are finally released. The public can now take advantage of the data accumulated from the D.E.O. 's years of studying metahuman powers and activities in the DC Universe.
This document expands on previously published material on powers. Get introduced to new ways of determining initial power cost, using Character Points and Hero Points with powers, and more. Find out how wonders and androids affect power selection. Learn more about new and revised limitations and enhancements. Discover a wealth of information on powers (new and updated), so many details that it took a whole book to contain them all."