Inform Designer’s Manual

The Inform Designer’s Manual, or “DM4″ as it is often called in the community, is a programming manual for Inform 6.

Inform 6 is no longer the latest version of Inform; Inform 7 is drastically different, and comes with its own built-in documentation. But the Designer’s Manual is far from obsolete, since it explains elements of Inform 6 that might be useful to advanced I7 users. It also includes a history of interactive fiction from the beginnings through the year 2000, and an essay called “Craft of Adventure” that has become a community classic.

The book is also available to read online and can be downloaded as a PDF or zipped HTML files.