Add some background information [ci skip]

README.md

@@ -11,6 +11,28 @@ HarfTeX achieves this by including widely used text layout and font loading
 libraries (such as [HarfBuzz][1] and ICU). That is while keeping the ability
 for its users to replace the text layout engine.
 
+Background
+----------
+
+LuaTeX does not provide native support for text layout other than what TeX
+originally provided, and instead provide hooks to its internals and Lua
+scripting capabilities that allow users (or macro packages) to provide such
+support.
+
+While this is a worthwhile goal, the complexity of text layout and font
+processing means developing such support from scratch is a complex,
+time-consuming task that also needs active ongoing development. This resulted
+in practically having only one text layout engine for LuaTeX written by the
+ConTeXt team (available through the [`luaotfload`][2] package for LaTeX and
+Plain TeX). Though it is a very capable engine, it falls short of supporting
+many world writing systems or some advanced text layout capabilities.
+
+HarfTeX started as an attempt to integrate the HarfBuzz text layout library
+into LuaTeX as a Lua module and a Lua support package, allowing users to
+benefit from a mature, well supported and featureful text layout engine.
+However, the LuaTeX team preferred to avoid the extra dependencies and
+suggested building a separate engine instead.
+
 Building
 --------
 
@@ -21,3 +43,4 @@ the script for a list of the options it take):
 
 
 [1]: https://github.com/harfbuzz/harfbuzz
+[2]: https://github.com/u-fischer/luaotfload