dco/c++ is a flexible and efficient implementation of first- and higher-order tangent and adjoint Algorithmic Differentiation (AD) by operator overloading in C++. It combines a cache-optimized internal representation based on C++ expression templates with an intuitive and powerful application programmer interface. It also has bindings in Fortran and MATLAB. dco/c++ has been applied successfully to a number of numerical simulations in the context of, for example, large-scale parameter estimation, shape optimization, or computational finance. dco/c++ is under active development. This report provides a basic reference in form of a brief introduction to derivative code resulting from the application of AD to numerical simulation programs, a description of the four fundamental differentiation modes (first- and second-order tangent and adjoint modes, respectively) and a list of all features of the current version of dco/c++. An in-depth discussion of the latter is beyond this document. Further information on the tool can be obtained by contacting info@stce.rwth-aachen.de.