  This work presents the first comprehensive study of structure formation at
the peak epoch of cosmic star formation over $1.4\leq z \leq 3.6$ in the COSMOS
field, including the most massive high redshift galaxy proto-clusters at that
era. We apply the extended COSMIC BIRTH algorithm to account for a multi-tracer
and multi-survey Bayesian analysis at Lagrangian initial cosmic times.
Combining the data of five different spectroscopic redshift surveys
(zCOSMOS-deep, VUDS, MOSDEF, ZFIRE, and FMOS-COSMOS), we show that the
corresponding unbiased primordial density fields can be inferred, if a proper
survey completeness computation from the parent photometric catalogs, and a
precise treatment of the non-linear and non-local evolution on the light-cone
is taken into account, including (i) gravitational matter displacements, (ii)
peculiar velocities, and (iii) galaxy bias. The reconstructions reveal a
holistic view on the known proto-clusters in the COSMOS field and the growth of
the cosmic web towards lower redshifts. The inferred distant dark matter
density fields concurrently with other probes like tomographic reconstructions
of the intergalactic medium will explore the interplay of gas and dark matter
and are ideally suited to study structure formation at high redshifts in the
light of upcoming deep surveys.
