This package implements the core funtionality of the Hierarchical Triangular Mesh (HTM) library. Some example in edu.jhu.htm.app show how to use the library. The lowest level HTM functions may be utilised directly from HTMfunc. A higher level interface is provided through HTMindex. Currently the only implementation of this interface is the HTMindexImp. Areas of the sky may be defined using Domains - to read these from files use one of the parsers in edu.jhu.htm.parsers. For higher level acces to domains use the classes in edu.jhu.htm.geometry i.e. to define a rectangle on the sky. There is and ant build.xml file in the distribuition for building the code and running the tests.