COLLOQUIUM PAPER. For the article “Synthetic zeolites and other microporous oxide molecular sieves” by John D. Sherman, which appeared in number 7, March 30, 1999, of Proc. Natl. Acad. Sci. USA (96, 3471–3478), the author notes the following corrections: (i) in Linear Paraffins for Biodegradable Detergents, OP ADS-34

should read UOP ADS-34; and (ii) in Impacts of Molecular Sieves on Human Welfare, the phrase, “From these numbers,” should be deleted.