In collaboration with one of its user groups, the SRC has installed a new planar electromagnetic undulator (EMU) on the Aladdin storage ring. Field quality, and resulting radiation-performance of the device, are sufficiently close to the ideal that no shimming was required. With slight exception, only minor, anticipated adaptation onto the Aladdin ring was needed to meet strict operational requirements. Major details of the design, fabrication, ex-citu and in situ testing, and commissioning are presented. DESIGNThe EMU described here serves as a source for a high-resolution normal-incidence monochromator (NIM) beamline that covers the range from 6-40 eV [1]. The device was designed by SRC and constructed jointly with the Physical Sciences Laboratory (UW-Madison). The electromagnetic type was chosen for a number of reasons: favorable experience with a similar device for Iowa State University [2]; excellent field-quality control made possible with a copperiron geometry; and conventional construction that both uses inexpensive materials and enables in-house fabrication, leading to substantial cost savings.