The five Symposia on Advances in Tracer Methodology were held annually from 1957 to 1961. The symposia were directed to scientists who are active in utilizing tracer techniques to help solve their scientific problems. The format, an informal one-day meeting consisting of about ten papers and closing with a cocktail hour, fostered an active exchange of information among speakers and audience. Although the first two symposia were restricted to the use of tritium as a tracer isotope, the larger purpose of the meetings was to disseminate information relating to the entire isotopic tracer field. The sponsoring organizations, all actively engaged in selling products in the nuclear field, attempted to provide a noncom­ mercialized forum which would facilitate this exchange of in­ formation. The collection of papers presented herein represents most of the talks presented at the first symposia plus several appropriate papers which have appeared either in Atomlight, the bulletin of the New England Nuclear Corp., or which have been submitted directly for inclusion in this collection. Although each of the authors was given the opportunity to revise his paper, it is likely that some of the techniques or instrumentation described may already have been outmoded by recent improvements.