Solid monolayer formation by all the linear amines from C-6 to C-16 adsorbed from their liquids to a graphite surface is demonstrated. Shorter homologues do not show such solid monolayer formation. The behavior is interpreted in terms of the competition between the alkyl chains, which favor solid monolayer formation, and the amine group, which does not. Nonylamine (C-9) also shows evidence of a solid-solid phase transition in the monolayer prior to melting.