Starting FORTH

About the book

Starting FORTH introduces the FORTH programming language, a stack-based system in which words operate on a data stack and programs grow by defining new words from existing ones. The book addresses readers who want to learn the language from its fundamentals rather than through a reference manual. Brodie builds the material around the language's distinctive model: values go on a stack, words consume and produce stack items, and the programmer extends the vocabulary of the system with each definition.

The book's subject is the language itself and the style of thinking it encourages. FORTH rewards decomposition: a problem is broken into small words, each tested and then combined. Brodie explains stack notation, arithmetic words, control structures, and the mechanics of defining new words, using worked examples to show how the pieces fit. The presentation assumes some familiarity with programming concepts and treats FORTH as a new way to organize computation, not as a dialect of a more familiar language.

Because FORTH exposes the stack directly, the book spends real effort on reading stack effects and tracing values through a sequence of words. That emphasis makes the text useful for anyone curious about concatenative languages and about how a minimal runtime can support substantial programs.

How to read it

Read with a FORTH system at hand, or at least a stack diagram on paper. The examples are short, but the stack changes with every word, and tracking those changes is the core skill the book teaches. Work the definitions yourself rather than reading them passively. The language's economy becomes clear once you have built a few words and seen them compose.

The prose is plain and example-driven, with diagrams and illustrations that carry much of the explanation. Expect to move slowly through the early stack material and faster once the notation becomes familiar. Later sections on control flow and defining words reward a second pass, because the same mechanisms recur in more complex definitions.

Who it suits

This suits programmers who want a grounded introduction to stack-based programming and to a language designed around small, testable definitions. Readers interested in minimalist systems, language design, or the history of personal computing will find the model instructive. Beginners to programming in general should start elsewhere; the book assumes comfort with variables, control flow, and debugging in some other language.

Reading considerations

The book reflects the FORTH systems and hardware of its era, and standard vocabularies and available implementations have changed since. Check which FORTH standard or implementation you plan to use, because word names and behaviors can differ. Treat the book as a guide to the language's ideas and idioms, and verify specifics against current documentation for your system.