The atmosphere is so remarkably complex that determining why a forecasted storm behaves as it does, why it takes a particular path, or why it intensifies, can be extremely difficult. One way to attack this challenging problem is to examine it in a linear framework. Tangent linear and related adjoint versions of numerical forecast models allow us to do that. Adjoint-based tools can provide valuable insight into how distinct atmospheric phenomena on various space and time scales, often separated by substantial distances, may evolve to interact and influence each other.  In this presentation, adjoint-based tools are used to explore both remote interactions and internal processes that influence the evolution and predictability of tropical and extratropical cyclones.