Unified Field Theory
The greatest unsolved question of physics, ever since relativity and quantum theory were developed in the early 20th century, has been the development of a single theoretical framework for describing the four forces of electromagnetism, gravity and strong and weak nuclear forces. This task also involves bridging between the quantum and classical realms, since two of the forces in question are only observable at the quantum level.
We may speculate about the attributes such a 'theory of everything' would have, if it existed. Among these, we would list:
Simultaneous inclusion of the concepts of general relativity and quantum theory.
A concept of irreversible event and entropy. A model for describing what constitutes observation and a description of the need for consciousness as an observer for determining the outcome of physical processes. Non-Locality A definition of causality, including possible causal loops and branching timelines.
In official academic science, string theory and quantum gravity are the leading approaches for building a unified field theory. Progress has been very limited and it is possible that research is being purposely steered towards extremely complex and ultimately fruitless pursuits by those already in possession of the theory. Also, researchers have been known to unexpectedly die following inquiry into the "wrong" subjects.
Engineering applications of such a theory would be essentially limitless, probably including free energy, control of gravity, manipulation of spacetime metric, time travel and other things. A formal understanding of the concept of density as used by Cassiopaeans would also be a likely outcome of having such a theory.
It is possible that such a theory has at least in part been discovered in very restricted circles. These same circles may also have received assistance in these pursuits from 4D STS. The Philadelphia Experiment was an early clandestine attempt at working with a partly developed UFT for affecting invisibility. However the effects were much stranger than expected and subsequent research has been done under still deeper cover, thus almost no information has leaked and what leaks there may be are most likely deliberate disinformation.