Forth is a language with token-oriented syntax and stack-based execution semantics. It has proven to be most successful in embedded real-time control systems.

Links of Relevance

The home page of the Forth Interest Group (FIG)
The UK chapter of FIG
The Russian chapter of FIG

ForthFreak: a wiki web site

The Forth programming webring

A collection of Forth information
ANS Forth definition (also here)

The Forth-83 standard

A beginner’s guide to Forth

Articles on Forth’s philosophy and use as an embedded language in high performance chips
FORTH – A Language for Interactive computing (also scanned): Charles Moore’s 1970 article that made the language known to the world

The Forth research page: an introduction to the language and links to other resources

Forth – the early years, by Charles Moore

The evolution of Forth: a detailed history of the language

Overviews of Machine Forth and colorForth, and an example of the latter (see below for colorForth)

Forth: an underview (an introduction to the language, its method and philosophy)

Lists of articles: 1, 2

colorForth quick start guide (see below for colorForth)

Books freely available online:
Starting Forth (also here), by Leo Brodie
A reconstructed version of Thinking Forth, by Leo Brodie
Programming Forth
Forth guide
And so Forth …
Stack computers: the new wave (not just Forth)
Freely available implementations:
colorForth: Moore’s current dialect of Forth; a version for Windows,
Gforth: the GNU implementation of ANS Forth
MinForth: a minimalistic but complete Forth system
pForth: a portable ANS Forth
ATLAST: a Forth-83 style scripting language, formerly used in AutoCAD
Ficl: an embeddable interpeter to be used as a scripting or macro language
4im: a compact, ‘neoclasic’ Forth
4tH: a compiler
Delta Forth .NET: a compiler for the .NET platform
RetroForth: a small, adaptable Forth
jsforth: a web-based implementation in JavaScript
volksFORTH: an 8- and 16-bit Forth system