  This paper formulates a bilateral account of harmony that is an alternative
to one proposed by Francez. It builds on an account of harmony for unilateral
logic proposed by K\"urbis and the observation that reading the rules for the
connectives of bilateral logic bottom up gives the grounds and consequences of
formulas with the opposite speech act. I formulate a process I call 'inversion'
which allows the determination of assertive elimination rules from assertive
introduction rules, and rejective elimination rules from rejective introduction
rules, and conversely. It corresponds to Francez's notion of vertical harmony.
I also formulate a process I call 'conversion', which allows the determination
of rejective introduction rules from assertive elimination rules and
conversely, and the determination of assertive introduction rules from
rejective elimination rules and conversely. It corresponds to Francez's notion
of horizontal harmony. The account has a number of features that distinguishes
it from Francez's.
