Research into gluten sensitivity has never been more popular nor more exciting. Thus a call for a new book, Celiac Disease: Methods and Prools, devoted entirely to techniques and technology seemed a most appropriate undertaking. I am therefore grateful to Professor J. M. Walker for inviting me to complete this task for Humana Press. To do this would have been imp- sible without the contributions of friends and colleagues from around the world who have devoted so much interest to the project. It has also been necessary for them to master the unique chapter-writing skills required of every ma- script published in this series of laboratory monographs. With regard to gluten sensitivity we are in a period of great change, occasioned by the introduction of reproducible methods for cloning lymp- cytes, the application of physical methods to identify gluten sequences as T-cell antigens, the study of peptide responses in vitro and in vivo by either jejunal or rectal challenge, elucidating the locations of other genes concerned in pathogenesis, or the use of elegant immunohisyhemical and mRNA probing techniques for analyzing the finer points of the mucosal inflam- tory response to gluten.