This book examines themes ranging from space time symmetries and Lorentz invariance, to cosmology and quantum gravity, and includes such varied mathematical tools as non-commutativity, superconformal symmetries, gauge theories, higher-order terms and spinor equations to name a few. In particular, this book deals with the problem of form-invariance of the non-commutative parameters arising in the context of field theories in non-commutative space times.