  The evolution of galaxies at Cosmic Noon (redshift 1<z<3) passed through a
dust-obscured phase, during which most stars formed and black holes in galactic
nuclei started to shine, which cannot be seen in the optical and UV, but it
needs rest frame mid-to-far IR spectroscopy to be unveiled. At these
frequencies, dust extinction is minimal and a variety of atomic and molecular
transitions, tracing most astrophysical domains, occur. The future IR space
telescope mission, SPICA, currently under evaluation for the 5th Medium Size
ESA Cosmic Vision Mission, fully redesigned with its 2.5 m mirror cooled down
to T < 8K will perform such observations. SPICA will provide for the first time
a 3-dimensional spectroscopic view of the hidden side of star formation and
black hole accretion in all environments, from voids to cluster cores over 90%
of cosmic time. Here we outline what SPICA will do in galaxy evolution studies.
