twoside – Two-side typesetting in Plain TeX
Defines macros that produce output destined for two-sided printing, with a gutter margin as specified by the user. A running head may also be specified.
Maybe you are interested in the following packages as well.
- letter-plain: Letter macros for Plain TeX
- lettermac: Simple macros for writing letters (Plain TeX)
- histyle: A "HighStyle" environment for TeX
- letter1: Letter formatting macros