Spectral energydistribution (SED):light emitted over allor a portion of theFUV-FIR spectraldomain, includingbroadband data and/ormoderate-resolutionspectraSFH:star-formationhistoryIMF:initial massfunctionFUV:far-ultravioletFIR:far-infraredNIR:near-infraredSPS:stellarpopulation synthesisAGB:asymptoticgiant branchHB:horizontalbranch1. INTRODUCTIONMany of the fundamental properties of unresolved stellar populations are encoded in their spectralenergy distributions (SEDs). These properties include the star-formation history (SFH), stellarmetallicity and abundance pattern, stellar initial mass function (IMF), total mass in stars, and thephysical state and quantity of dust and gas. Some of these properties are easier to measure thanothers, and each provides important clues regarding the formation and evolution of galaxies. It isprecisely these quantities, measured from the SEDs of galaxies, that have provided the foundationfor our modern understanding of galaxy formation and evolution.Over the past several decades considerable effort has been devoted to extracting informationfromtheSEDs ofgalaxies,exploitinginformationfromthefar-ultraviolet (FUV)tothefar-infrared(FIR). Early attempts at understanding the visible and near-infrared (NIR) spectral windowsapproached the problem by combining mixtures of stars in ad hoc ways until a match was achievedwith observations (e.g., Spinrad & Taylor 1971). More sophisticated versions of this techniquewere developed that incorporated physical constraints and automated fitting techniques (Faber1972). At approximately the same time, synthesis models were being developed that relied on stellar
