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-Chez Scheme is a compiler and run-time system for the language of
-the Revised<sup>6</sup> Report on Scheme (R6RS), with numerous extensions.
-The compiler generates native code for each target processor, with
-support for x86, x86_64, and 32-bit PowerPC architectures.
+Chez Scheme is both a programming language and an implementation
+of that language, with supporting tools and documentation.
 
-Get started by [Building Chez Scheme](BUILDING).
+As a superset of the language described in the
+[Revised<sup>6</sup> Report on the Algorithmic Language Scheme](http://www.r6rs.org)
+(R6RS), Chez Scheme supports all standard features of Scheme,
+including first-class procedures, proper treatment of tail calls,
+continuations, user-defined records, libraries, exceptions, and
+hygienic macro expansion.
+
+Chez Scheme also includes extensive support for interfacing with C
+and other languages, support for multiple threads possibly running
+on multiple cores, non-blocking I/O, and many other features.
+
+The Chez Scheme implementation consists of a compiler, run-time
+system, and programming environment.
+Although an interpreter is available, all code is compiled by
+default.
+Source code is compiled on-the-fly when loaded from a source file
+or entered via the shell interface.
+A source file can also be precompiled into a stored binary form and
+automatically recompiled when its dependencies change.
+Whether compiling on the fly or precompiling, the compiler produces
+optimized machine code, with some optimization across separately
+compiled library boundaries.
+The compiler can also be directed to perform whole-program compilation,
+which does full cross-library optimization and also reduces a
+program and the libraries upon which it depends to a single binary.
+
+The run-time system interfaces with the operating system and supports,
+among other things, binary and textual (Unicode) I/O, automatic
+storage management (dynamic memory allocation and generational
+garbage collection), library management, and exception handling.
+By default, the compiler is included in the run-time system, allowing
+programs to be generated and compiled at run time, and storage for
+dynamically compiled code, just like any other dynamically allocated
+storage, is automatically reclaimed by the garbage collector.
+
+The programming environment includes a source-level debugger, a
+mechanism for producing HTML displays of profile counts and program
+"hot spots" when profiling is enabled during compilation, tools for
+inspecting memory usage, and an interactive shell interface (the
+expression editor, or "expeditor" for short) that supports multi-line
+expression editing.
+
+The R6RS core of the Chez Scheme language is described in
+[The Scheme Programming Language](http://www.scheme.com/tspl4/),
+while Chez Scheme's additional language, run-time system, and
+programming environment features are described in the
+[Chez Scheme User's Guide](http://cisco.github.io/ChezScheme/csug9.4/csug.html).
+The latter includes a shared index and a shared summary of forms,
+with links where appropriate to the former, so it is often the best
+starting point.
+
+Get started with Chez Scheme by [Building Chez Scheme](BUILDING).
 
 For more information see the [Chez Scheme Project Page](https://cisco.github.io/ChezScheme/).