Contents

06 June 1997
Vol 276, Issue 5318

About The Cover

Ruth and Annié Nyström are 93-year-old monozygotic Swedish twins who are participants in "OCTO-Twin," a longitudinal study on genetic and environmental influences on individual differences in aging funded by the National Institute on Aging. The study involves same-sex twins 80 or more years of age and measures a broad array of behavioral variables. The report in this issue focuses on cognitive functioning. See 1560 and the related Perspective on 1522. [Collage: Preston Morrighan, also an identical twin]