# [Overview](@id classes-overview)
The data members of fundamental classes in HiGHS are defined in this section.
* [HighsSparseMatrix](@ref)
* [HighsLp](@ref)
* [HighsHessian](@ref)
* [HighsModel](@ref)
* [HighsIis](@ref)
Class data members for internal use only are not documented.