  We review the charged particle and photon multiplicity, and transverse energy
production in heavy-ion collisions starting from few GeV to TeV energies. The
experimental results of pseudorapidity distribution of charged particles and
photons at different collision energies and centralities are discussed. We also
discuss the hypothesis of limiting fragmentation and expansion dynamics using
the Landau hydrodynamics and the underlying physics. Meanwhile, we present the
estimation of initial energy density multiplied with formation time as a
function of different collision energies and centralities. In the end, the
transverse energy per charged particle in connection with the chemical
freeze-out criteria is discussed. We invoke various models and phenomenological
arguments to interpret and characterize the fireball created in heavy-ion
collisions. This review overall provides a scope to understand the heavy-ion
collision data and a possible formation of a deconfined phase of partons via
the global observables like charged particles, photons and the transverse
energy measurement.
