  This paper presents key aspects of the quantum relativistic direct-action
theory that underlies the Relativistic Transactional Interpretation. It notes
some crucial ways in which traditional interpretations of the direct-action
theory have impeded progress in developing its quantum counterpart.
Specifically, (1) the so-called 'light tight box' condition is re-examined and
it is shown that the quantum version of this condition is much less restrictive
than has long been assumed; and (2) the notion of a 'real photon' is
disambiguated and revised to take into account that real (on-shell) photons are
indeed both emitted and absorbed and therefore have finite lifetimes. Also
discussed is the manner in which real, physical non-unitarity naturally arises
in the quantum direct-action theory of fields, such that the measurement
transition can be clearly defined from within the theory, without reference to
external observers and without any need to modify quantum theory itself. It is
shown that field quantization arises from the non-unitary interaction.
