The report gives a defining description of the programming language Scheme. Scheme is a statically scoped and properly tail-recursive dialect of the Lisp programming language invented by Guy Lewis Steele Jr. and Gerald Jay Sussman. It was designed to have an exceptionally clear and simple semantics and few different ways to form expressions. A wide variety of programming paradigms, including functional, imperative, and message passing styles, find convenient expression in Scheme.

This report is accompanied by a report describing standard libraries [22]; references to this document are identified by designations such as “library section” or “library chapter”. It is also accompanied by a report containing non-normative appendices [23]. A third report gives some historical background and rationales for many aspects of the language and its libraries [24].

The individuals listed above are not the sole authors of the text of the report. Over the years, the following individuals were involved in discussions contributing to the design of the Scheme language, and were listed as authors of prior reports:

Hal Abelson, Norman Adams, David Bartley, Gary Brooks, William Clinger, R. Kent Dybvig, Daniel Friedman, Robert Halstead, Chris Hanson, Christopher Haynes, Eugene Kohlbecker, Don Oxley, Kent Pitman, Jonathan Rees, Guillermo Rozas, Guy L. Steele Jr., Gerald Jay Sussman, and Mitchell Wand.

In order to highlight recent contributions, they are not listed as authors of this version of the report. However, their contribution and service is gratefully acknowledged.

We intend this report to belong to the entire Scheme community, and so we grant permission to copy it in whole or in part without fee. In particular, we encourage implementors of Scheme to use this report as a starting point for manuals and other documentation, modifying it as necessary.

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This is a preliminary draft. It is intended to reflect the decisions taken by the editors’ committee, but likely contains many mistakes, ambiguities, and inconsistencies.