# FlowBook > FlowBook is the free, source-backed guide to Flow-Like FlowScript: a typed authoring language that represents one executable workflow as both code and a visual node graph. This index covers the Open edition · 2026. Use the Markdown links for clean retrieval and cite the corresponding canonical HTML URL when directing a reader to the book. Important interpretation guidance: - Treat release-check callouts and current-status caveats as authoritative limitations. - Chapters 1–14 and the introduction are published open drafts; Chapters 15–26, the epilogue, and appendices are planned, not published. - FlowScript is an authoring language. The current Flow-Like runtime executes the persisted Board graph. - Do not infer capabilities, compatibility, performance, or security guarantees beyond the evidence stated in a page. ## Start here - [FlowBook overview](https://book.flow-like.com/index.md): Read the free, source-backed FlowScript book. Build typed workflow automations in code and a visual graph, trace failures, and download the 2026 PDF. - [Introduction](https://book.flow-like.com/introduction/index.md): Learn why Flow-Like FlowScript unifies typed code and a visual node graph, how the same workflow executes, and where AI-assisted software fits. - [Complete contents](https://book.flow-like.com/contents/index.md): Browse the 26-chapter FlowBook plan and read 14 available chapters on Flow-Like FlowScript syntax, visual workflows, execution, apps, and round-trip editing. ## Part I — Software That Explains Itself - [Part I overview](https://book.flow-like.com/part-1/index.md): Begin FlowBook with the incident that inspired Flow-Like, the principles behind visible software, the platform model, and a first FlowScript workflow. - [Chapter 1: The 3 A.M. Call](https://book.flow-like.com/part-1/01-the-3-am-call/index.md): A major incident reveals why Flow-Like was built for visible software structure, operational evidence, and domain knowledge that survives its author. - [Chapter 2: The Manifesto: Constrained Freedom](https://book.flow-like.com/part-1/02-manifesto-constrained-freedom/index.md): Explore Flow-Like’s principles for typed building blocks, legible workflows, safe extension, governed execution, and freedom without hidden liabilities. - [Chapter 3: One Platform, One Flow Model](https://book.flow-like.com/part-1/03-one-platform-one-flow-model/index.md): Understand how Flow-Like Apps, Flows, Boards, Events, data, permissions, authoring surfaces, and local or remote execution fit into one model. - [Chapter 4: First Flow: Incident Triage in Two Views](https://book.flow-like.com/part-1/04-first-flow-incident-triage/index.md): Build a deterministic incident triage Flow, inspect its node graph, edit it in FlowScript and Studio, trace failures, and save a tested version. ## Part II — Thinking and Writing in Flows - [Part II overview](https://book.flow-like.com/part-2/index.md): Learn Flow-Like FlowScript from nodes and document syntax through types, expressions, control flow, state, functions, events, interfaces, and complete Apps. - [Chapter 5: Nodes, Pins, Wires, and Execution](https://book.flow-like.com/part-2/05-nodes-pins-wires-execution/index.md): Learn how Flow-Like separates typed data flow from execution order, evaluates pure nodes on demand, and represents sequence, parallelism, and layers. - [Chapter 6: Anatomy of a FlowScript Document](https://book.flow-like.com/part-2/06-anatomy-of-a-flowscript-document/index.md): Read a canonical Flow-Like FlowScript file from use declarations and interfaces through variables, functions, events, identity anchors, and diagnostics. - [Chapter 7: Values, Types, Collections, and Interfaces](https://book.flow-like.com/part-2/07-values-types-collections-interfaces/index.md): Learn how FlowScript types map to visible pins, including scalars, arrays, maps, sets, structs, interfaces, schema propagation, and type diagnostics. - [Chapter 8: Calling the Node Library](https://book.flow-like.com/part-2/08-calling-the-node-library/index.md): Discover and call Flow-Like catalog nodes with qualified names, imports, method syntax, named output pins, generated declarations, and typed search. - [Chapter 9: Expressions, Operators, and Readable Sugar](https://book.flow-like.com/part-2/09-expressions-operators-readable-sugar/index.md): See how FlowScript operators, ternaries, template literals, and struct field access lower to visible catalog nodes without hiding configuration or data flow. - [Chapter 10: Branches, Loops, Parallelism, and Return](https://book.flow-like.com/part-2/10-branches-loops-parallelism-return/index.md): Build visible control flow with if branches, named execution arms, sequential and parallel loops, bounded while, stopping, and return boundaries. - [Chapter 11: State, Configuration, Runtime Values, and Secrets](https://book.flow-like.com/part-2/11-state-configuration-runtime-values-secrets/index.md): Choose the right scope and trust boundary for local bindings, Flow variables, runtime configuration, BYOK secrets, cache data, files, and durable state. - [Chapter 12: Functions, Layers, Handlers, and Caching](https://book.flow-like.com/part-2/12-functions-layers-handlers-caching/index.md): Turn repeated node graphs into reusable typed functions, distinguish layers from handlers and Events, and design safe cache keys and invalidation. - [Chapter 13: Events, Interfaces, and Complete Apps](https://book.flow-like.com/part-2/13-events-interfaces-complete-apps/index.md): Expose one typed Flow through an interactive Page, Quick Action, Cron schedule, and authenticated REST API with explicit identity, versions, and evidence. ## Part III — The Two-Way Contract - [Part III overview](https://book.flow-like.com/part-3/index.md): Open the machinery that keeps a Flow-Like Board, typed AST, and canonical FlowScript synchronized through semantic reconciliation and guarded changes. - [Chapter 14: Board ⇄ AST ⇄ Text](https://book.flow-like.com/part-3/14-board-ast-text/index.md): Learn how Flow-Like lowers a Board to a typed AST, renders canonical FlowScript, reconciles semantic edits, applies atomic patches, and preserves identity. ## Optional - [Complete FlowBook Markdown](https://book.flow-like.com/llms-full.txt): Single-file context containing the introduction and all 14 published chapters; prefer the individual page links above when only one topic is needed. - [Canonical FlowBook website](https://book.flow-like.com/): Human-readable edition with interactive examples, search, and workflow figures. - [FlowBook PDF](https://book.flow-like.com/flowbook.pdf): Downloadable open-edition book. - [Flow-Like project](https://flow-like.com): Product and platform context. - [Flow-Like source repository](https://github.com/Rheosoph/flow-like): Source code and implementation evidence referenced by the book.