  In this Ph.D. thesis, we study various backgrounds in Type IIB supergravity
which admit interpretations in terms a dual field theory, and compute
properties such as effective potentials and spectra, using both holographic and
field theoretic methods. First, we study the phase structure of beta-deformed
N=4 SYM on S3 at weak and strong 't Hooft coupling. We compute the one-loop
effective potential, and find that at near critical chemical potential and
small finite temperature, there is a metastable state at the origin of moduli
space. We derive the gravitational background describing the theory at strong
coupling, and by performing a probe-brane calculation, we find qualitative
agreement between the weak and strong coupling results. Next, we study
gravitational backgrounds obtained by wrapping Nc D5 color branes on an S2
inside a CY3-fold, and Nf D5 backreacting flavor branes on a non-compact
two-cycle inside the same CY3-fold. These backgrounds are believed to be dual
to certain SQCD-like theories. We compute how the spectrum depends on the
number of flavors, and find that the mass of the lightest scalar glueball
increases with the number of flavors until the point Nf=2Nc is reached after
which the opposite behaviour is observed. Finally, we consider a class of
backgrounds that exhibit walking behaviour, i.e. a suitably defined
four-dimensional gauge coupling stays nearly constant in an intermediate energy
regime. The breaking of approximate scale invariance has been conjectured to
lead to the existence of a light scalar in the spectrum. This so-called dilaton
would be the pseudo-Goldstone boson of dilatations. Using holographic
techniques, we compute the spectrum and find a light state whose mass is
suppressed by the length of the walking region, suggesting that this might be
the dilaton.
