The 'interpsychic' is an extended psychic dimension, regarding the joint functioning and reciprocal influences of two minds. The concepts of 'subjectivity' and 'person' can be included in the 'interpsychic'. They can also overlap with each other, and sometimes all three can overlap together, but they do not necessarily coincide. In the different contemporary perspectives, how can we modify the intrapsychic 'through' (and 'with' and 'by') the interpsychic? Presenting four clinical vignettes, the author progressively moves from the theoretical positions that emphasise the exploration and the elaboration of the intrapsychic mainly through the intrapsychic, to the positions that emphasise the same operations mainly through the interpsychic. The last part of the paper deals with the technical use of the interpsychic dimension: the analytic dialogue, when interpsychically experienced (from inside), gains a new, more specific effectiveness, first in containing and then in symbolising. In an intense mental 'cohabitation' inside the analytic working pair, it is very often clearly experienced as 'true' (as in dreams).