"HERA" (the Haverford Educational RISC Architecture) is a simplified microprocessor architecture used at Haverford College to draw connections among the upper-level applied CS courses. This short book describes the instruction set architecture and describes common programming idioms. The information in it (except the front cover) is also available from the HERA web site, cs.haverford.edu/software/HERA. For information about the educational goals and uses of HERA, see the proceedings of the CCSC-E 2006 conference.