THE L-SHELL X-RAY SPECTRUM OF IRON DOMINATES THE EMISSION FROM MANY HOT ASTROPHYSICAL OBJECTS AS DEMONSTRATED EARLY ON WITH ASCA AND CURRENTLY BY THE SUPERB SPECTRA OBSERVED WITH CHANDRA'S HIGH-ENERGY GRATING SPECTROMETER. THE UPCOMING X-RAY IMAGING AND SPECTROSCOPY MISSION (XRISM) WILL OBSERVE THE FE L-SHELL X-RAY EMISSION FROM EXTENDED OBJECTS TOGETHER WITH THE ASSOCIATED FE K-SHELL X-RAY EMISSION. BECAUSE COLLISIONAL EXCITATION CROSS SECTIONS FROM THE L SHELL ARE ALMOST AN ORDER OF MAGNITUDE LARGER THAN THOSE FROM THE K SHELL THE L-SHELL EMISSION MAY DOMINATE THE OBSERVED SPECTRA FROM ALL BUT THE VERY HOTTEST OBJECTS. THE MOST PROMINENT LINES IN THE L-SHELL SPECTRUM OF IRON ARE OFTEN FROM FE XVII. HOWEVER LINES FROM OTHER CHARGE STATES UP TO FE XXIV MAY CONTRIBUTE PROFUSELY. IN ORDER TO UNDERSTAND THE FE L-SHELL EMISSION OBSERVED BY PAST AND CURRENT MISSIONS LABORATORY MEASUREMENTS WERE NEEDED TO MAKE SENSE OF A VERITABLE FOREST OF LINES FROM FE XVIII THROUGH FE XXIV I.E. FROM IRON IONS WITH AN OPEN L SHELL. ASTROPHYSICAL MODELS ORIGINALLY HAD LINES IN THE WRONG PLACE OR OMITTED MANY OF THESE LINES ALTOGETHER. THE LABORATORY MEASUREMENTS PROVIDED LINE IDENTIFICATIONS ACCURATE LINE ENERGIES RELATIVE INTENSITIES AND EXCITATION CROSS SECTIONS. BECAUSE MOST OF THE MISSING LINES FROM FE XVIII THROUGH FE XXIV WERE SITUATED AT THE SHORT-WAVELENGTH SEGMENT OF THE FE XVII EMISSION THE FOCUS OF THE LABORATORY MEASUREMENTS WAS ON LINES WITH WAVELENGTHS BELOW 16.35 (ABOVE 760 EV). THE HISTORICAL ASSUMPTION WAS THAT THE LONGER-WAVELENGTH REGION ABOVE 16.3 DID NOT CONTAIN ANY L-SHELL X-RAY LINES FROM IRON IONS WITH AN OPEN L SHELL BECAUSE NO SUCH LINES APPEARED IN CALCULATIONS. IN THE MEANTIME IT HAS BECOME CLEAR THAT OPEN L-SHELL IRON IONS HAVE LINES CONTRIBUTING TO THE LONG-WAVELENGTH SEGMENT OF THE FE L-SHELL X-RAY SPECTRUM. THESE LINES ARE ASCRIBED TO SO-CALLED "TWO-ELECTRON ONE-PHOTON" TRANSITIONS THE DESCRIPTION OF WHICH REQUIRES MORE COMPLEX CALCULATIONS THAN COULD BE HANDLED BY THE EARLY ATOMIC PHYSICS CODES. FOR EXAMPLE FE XIX LINES HAVE NOW BEEN PREDICTED AND INVOKED TO ANALYZE CHANDRA SPECTRA. HOWEVER NONE OF THESE LINES HAVE YET BEEN IDENTIFIED AND MEASURED IN THE LABORATORY. SIMILARLY ONLY ONE SUCH FE XVIII TRANSITION HAS SO FAR BEEN MEASURED AND IDENTIFIED IN LABORATORY MEASUREMENTS. THESE LINES SIGNIFICANTLY INCREASE THE (OTHERWISE UNFITTED) FLUX IN THIS REGION AND SOME BLEND WITH KNOWN LINES. BECAUSE ALL TWO-ELECTRON ONE-PHOTON TRANSITIONS FALL INTO THE LONG-WAVELENGTH PART OF THE FE L-SHELL X-RAY SPECTRUM THEIR OMISSION IN THE MODELS RESULTS IN A SYSTEMATIC DEFICIENCY IN THE FE L-SHELL SPECTRUM. ACCOUNTING FOR THESE LINES IS IMPORTANT FOR THE ANALYSES OF CURRENT CHANDRA SPECTRA WHERE UNIDENTIFIED FEATURES IN THE LONG-WAVELENGTH PART OF THE FE L-SHELL X-RAY SPECTRUM HAVE ALREADY STIMULATED THE NEED FOR A MORE COMPLETE LIST OF FE LINES. IT WILL BE ESPECIALLY IMPORTANT WHEN ANALYZING XRISM OBSERVATIONS WHERE THESE LINES WILL BE UNRESOLVED AND MERGE WITH STRONGER FEATURES OR THE CONTINUUM. TO ADDRESS THIS SYSTEMATIC DEFICIENCY WE PROPOSE TO MEASURE THE X-RAY TRANSITIONS FROM ALL OPEN L-SHELL IRON IONS CONTRIBUTING TO THE FE L-SHELL X-RAY SPECTRUM. THE MEASUREMENTS WILL BE CARRIED OUT AT THE LIVERMORE ELECTRON BEAM ION TRAP (EBIT) FACILITY AND UTILIZE SPECTROMETERS WITH RESOLVING POWERS SIMILAR TO CHANDRA'S HIGH ENERGY TRANSMISSION GRATING SPECTROMETER. MOREOVER THE EBIT X-RAY CALORIMETER SPECTROMETER A 6X6 ARRAY BUILT BY THE GODDARD SPACE FLIGHT CENTER WITH THE SAME SPECIFICATIONS AS HITOMI'S SXS AND XRISM'S RESOLVE CALORIMETER SPECTROMETERS WILL PROVIDE SIMULTANEOUS MEASUREMENTS OF THE FULL FE L-SHELL AND K-SHELL X-RAY EMISSION. OUR MEASUREMENTS WILL THUS ELIMINATE THE MOST SIGNIFICANT REMAINING DEFICIENCY IN THE LINE LIST OF THE FE L-SHELL X-RAY SPECTRUM AND ILLUSTRATE ITS EFFECT ON THE XRISM-TYPE CALORIMETER MEASUREMENTS.