  The precision measurements of Higgs boson observables will be critical in the
interpretation of the dynamics responsible for electroweak symmetry breaking.
The capabilities of the ILC and CLIC for precision Higgs studies are well
documented. In this talk, a theoretical framework is presented for interpreting
phenomena that can arise in the two-Higgs-doublet model (2HDM). By imposing no
constraints on the most general set of 2HDM parameters, the resulting formalism
correctly identifies the physical 2HDM observables, which can be determined by
model-independent experimental analyses.
