Jonathan Pearson obtained his PhD in Theoretical Cosmology at Jodrell Bank Centre for Astrophysics, at the University of Manchester. His research topics include: domain wall network dynamics, constructing gauged cosmic vortons, inhomogeneous universes and constructing a formalism to use observational data to constrain modified gravity theories.

• Gravitational theories and cosmology.- The effective action formalism for cosmological perturbations.- Metric only and first order scalar field theory.- High derivative theories.- Explicit theories.- Connections to massive gravity.- Generalized fluid description.- Observational signatures of generalized cosmological perturbations.- Discussion and final remarks.

Jonathan Pearson obtained his PhD in Theoretical Cosmology at Jodrell Bank Centre for Astrophysics, at the University of Manchester. His research topics include: domain wall network dynamics, constructing gauged cosmic vortons, inhomogeneous universes and constructing a formalism to use observational data to constrain modified gravity theories.

• Gravitational theories and cosmology.- The effective action formalism for cosmological perturbations.- Metric only and first order scalar field theory.- High derivative theories.- Explicit theories.- Connections to massive gravity.- Generalized fluid description.- Observational signatures of generalized cosmological perturbations.- Discussion and final remarks.

Jonathan Pearson obtained his PhD in Theoretical Cosmology at Jodrell Bank Centre for Astrophysics, at the University of Manchester. His research topics include: domain wall network dynamics, constructing gauged cosmic vortons, inhomogeneous universes and constructing a formalism to use observational data to constrain modified gravity theories.

• Gravitational theories and cosmology.- The effective action formalism for cosmological perturbations.- Metric only and first order scalar field theory.- High derivative theories.- Explicit theories.- Connections to massive gravity.- Generalized fluid description.- Observational signatures of generalized cosmological perturbations.- Discussion and final remarks.