Dear Colleague-- We are pleased to announce the joint release of Enzo 2.3 and the Enzo method paper, entitled "Enzo: An Adaptive Mesh Refinement Code for Astrophysics." Enzo 2.3 brings some new physics packages, improvements to the code, and some needed bug fixes. The method paper describes in detail the algorithms used for every physics package presented in this release, along with test problems and a description of the community development practices that have made the code so successful. The new physics modules in Enzo 2.3 include a constrained transport MHD method (MHDCT) and a new radiation background described by Haardt & Madau 2012, a PPM implementation for CUDA, and improvements to the CUDA MHD solver. Code improvements include MPI performance timers and improvements to the inline interface between Enzo and the analysis package yt, and several new problem types, including a cluster potential problem, a magnetic reconnection problem that utilizes the new MHDCT solver, and a particle orbit problem. Bug fixes to the gravity, chemistry, and radiation solvers are also included. The components of this release can be found by following these links: - The paper can be found here <http://arxiv.org/abs/1307.2265> - The code to reproduce the tests can be found at here<http://enzo-project.org/ReleaseNotes.html> - Enzo 2.3 can be found here <https://bitbucket.org/enzo/enzo-stable> - The continually updated development branch can be found here<https://bitbucket.org/enzo/enzo-dev> - A full list of changes can be found here<http://enzo-project.org/ReleaseNotes.html> - Documentation can be found at enzo-project.org <http://enzo-project.org/enzo-project.org>, along with links to the above. Sincerely, David Collins, on behalf of the Enzo Collaboration.