gwyddionenums — Common libgwyddion enumerations
GwySerializable — Abstract interface for serializable objects
GwyContainer — A container with items identified by a GQuark
gwymacros — Utility macros
gwyddion — Base functions, library initialization
gwyentities — Transform SGML-like symbol entities to UTF-8
gwymath — Mathematical utility functions
GwyNLFitter — Marquardt-Levenberg nonlinear least square fitter
GwyNLFitPreset — NL fitter presets
GwyExpr — Arithmetic expression parser and evaluator
GwySIUnit — SI unit representation, physical quantitiy formatting
gwyutils — Various utility functions
gwyversion — Version information
GwyEnum — String-integer value pair
GwyInventory — Ordered item inventory, indexed by both name and position.
GwyResource — Built-in and/or user supplied application resources
GwyStringList
gwymd5 — Compute MD5 digest
gwydebugobjects — Helps chasing leaking objects (debug)

This library contains basic classes and interfaces not directly related to GUI or data processing, and various utility functions.