The Inform Designer's Manual

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The primary source of written information about Inform 6 is The Inform Designer's Manual by Graham Nelson; the current fourth edition of this manual is often known as the DM4. (For a complementary manual aimed more directly at Inform novices, see The Inform Beginner's Guide.)

Note that both books describe Release 6 of Inform; they do not cover Inform 7, which pioneers a radically new approach to IF authorship based on natural language definitions.


The information is structured as eight major chapters, divided into some 50 subsections.

  • The Inform Language: presents the statements, operators and directives supported by the Inform 6 compiler.
  • Introduction to Designing: describes the structure of an Inform 6 source file, and the role of the library files; begins the "Ruins" example game.
  • The Model World: introduces the library's capabilities for creating a semi-realistic model of real world behaviour; extends the "Ruins" example game.
  • Describing and Parsing: controlling how objects are referred to, both by the game and by those playing it.
  • Natural Language: designing games in non-English languages.
  • Using the Compiler: controlling how the source file is compiled into a story file.
  • The Z-Machine: understanding the capabilities of Infocom's venerable virtual machine.
  • The Craft of Adventure: an essay on the principles behind good interactive fiction.

Scattered throughout the text are references to short demonstration programs — somewhat misleadingly called Exercises — showing how Inform can address common design problems; the model Answers are collected at the end of the manual. In addition, a series of appendices and tables summarise the features of the Inform language and library.

Known errors in the manual are listed here, and updates for changes to Inform 6 since DM4 was written in an addendum.


The manual is available as a free PDF download, or can be browsed online at its website or via Google Books. It is also available for purchase from any good bookstore in paperback (ISBN 0971311900,, and hardback (ISBN 0971311935,,

The original publisher of the printed edition of the DM4, in July 2001, was David Cornelson. After a period when the manual was out of print, in March 2006 the role of publisher was taken over by Dan Sanderson.

Revision History

  • Edition 1: September 1994 (describes Inform 5?)
  • Edition 2: October 1995 (describes Inform 5.5?)
  • Edition 3/1: September 1996 (describes Inform release 6.05, using library release 6/2?)
  • Edition 3/2: May 1997 (describes Inform release 6.13, using library release 6/5)
  • Edition 4/1: May 2001 (describes Inform release 6.21, using library release 6/9)
  • Edition 4/2: July 2001 (describes Inform release 6.21, using library release 6/9)