Rarely, if ever, are museum objects collected with the value of their atomic information in mind. Yet, frequently the isotopic composition of materials is used in authentication, sourcing, dating and even more complicated research questions. The light isotopes of carbon, nitrogen, oxygen and sulphur are an analytical quartet that are increasingly measured in museum specimens, cultural and biological. Light isotopes have been used extensively in archaeological and paleontological contexts to study past diets, ecosystems, home range, and climate. Similar analyses of cultural materials are expanding to explore sources, both geographical and etiological, of raw material. The impact of the museum environment and conservation treatments on the light isotopic composition of museum materials has been profound. By direct application of primarily carbon based materials, the iostopic configuration of many objects has been altered from the original with a concomitant loss of information. Cleaning procedures may as well remove information at the isotopic level that can not be retrieved. Finally, the overall lack of awareness of the value of museum objects at this fundamental level is evidenced in the overall museum environment. The acquisition of objects into museums occurs for many reasons: artistic, cultural, uniqueness, social importance, traditional and whimsy. The atomic constituents of materials are not considered in the decisions to procure museum objects. Yet, increasingly, the research value and information content at this most basic level are being used to answer questions regarding provenance, manufacture, and trade. Organic materials in museums, ranging from those imbedded in calcified tissue hard parts to fragile textiles, often pose a challenge in long term preservation. These natural products share the atomic constituents of carbon, nitrogen, oxygen, and sulphur that are now known to be the source of isotopic information used in interpretations that range from paleoenvironmental reconstruction to sourcing of geological materials. The museums of world, then, contain the record of past environments, past feeding strategies as well as past utilization of raw materials often associated with cultural materials. Many museum objects such as pottery, lithic tools, textiles, and basketss, as well as frank biological remains such as bones and teeth contain information not only in their morphology or style and in their construction, but also at the fundamental atomic level. One challenge in the curation and conservation of these materials is the impact of storage and treatmentt on atomic and molecular information. What was once thought of benign applications of preservatives can have catastrophic effects on isotopic analysis. This paper reviews the basic approach of light isotope ration mass spetrometry, and highlights case studies that have been applied to museum objects.