Glossary · 1 · Documentation models
Every page is page one
Also known as: EPPO, EPPO topic, Every Page is Page One (EPPO)
In technical communication, Every Page is Page One (EPPO) is a model for topic-based writing, set out by Mark Baker in the book of the same name (XML Press, 2013), in which every topic is designed to work as a reader's first page. It assumes that readers arrive from search, links, or in-product help rather than from a table of contents, so each topic has to carry its own context and purpose instead of relying on a preceding chapter. Baker describes seven characteristics of an EPPO topic: it is self-contained, has a specific and limited purpose, conforms to a type, establishes its context, assumes the reader is qualified, stays on one level, and links richly. EPPO is an authoring and information-architecture model, not a markup standard or a conformance scheme.
- documentation models
- topic-based authoring
- information architecture
- findability
- technical communication
In one sentence
Mark Baker's model for topic-based writing: every topic works as a reader's first page, with seven defining characteristics.
Example
During review, the team rejects a maintenance topic that starts with "After completing the steps above," because a reader reaching it from a search result has no "above" to rely on.
How it applies
- Treat every topic as an entry point. In help centers, portals, and in-product help, topics are reached by search, deep link, help ID, or a QR code on a machine. EPPO turns that observation into a writing rule: the topic states what it covers, for which product and version, and under which conditions — it does not inherit that framing from a parent chapter.
- Use the seven characteristics as a review checklist. Baker lists them as: self-contained; specific and limited purpose; conforms to a type; establishes its context; assumes the reader is qualified; stays on one level; links richly. Reviewers can ask one question per characteristic instead of debating style.
- "Assumes the reader is qualified" is a scoping decision, not an excuse to omit. The topic defines the reader it serves (for example a trained maintenance technician) and writes to that level, rather than re-teaching prerequisites in every topic. Required qualifications, tools, and machine states are still named explicitly, because the reader may have arrived without reading anything else.
- "Stays on one level" keeps granularity predictable. An overview topic stays an overview; a procedure stays a procedure. This aligns well with information typing — see DITA information typing and the type pairs concept, task, and reference — although EPPO leaves the set of types to the information set rather than prescribing one.
- "Links richly" replaces sequence with relationships. Instead of next/previous chains, topics link to neighboring subjects at the point where the subject is mentioned. Hierarchical navigation (DITA map) and faceted access built on metadata and a taxonomy remain useful, but they are not the only path to a topic.
- Implementation-neutral. EPPO can be realized in DITA topics, in an iiRDS topic, in Markdown in a docs-as-code pipeline, in a wiki, or in a PDF chapter — the model constrains topic design, not file format or schema.
- In machinery documentation, EPPO mostly affects maintenance, troubleshooting, and operating topics that are opened on the shop floor. Writing each one so it names the machine state, isolation steps, and qualified person makes it usable out of sequence; it does not by itself satisfy any legal requirement for information for use or instructions for use, which have to be assessed against the applicable rules.
- In software documentation, the model shows up as landing-page behavior: every anchor reachable from an in-app help call, a release note, or a support reply has to explain the feature's purpose and preconditions. API and CLI reference pages benefit most, because they are almost never read in order.
- Known trade-off with reuse. Repeating context in every topic can collide with the economics of single-sourcing and translation volume. Teams usually resolve this with short, consistent context blocks that are themselves reusable components, and they document the rule so the repetition is deliberate.
- On this site, the model is applied in practice in the EPPO Projects.
Every Page is Page One vs. topic-based authoring
Topic-based authoring describes how content is produced and managed: writing in discrete units that can be assembled, reused, and published to several outputs. EPPO describes how a topic must read for someone who lands on it cold. The two are compatible but not identical — a topic set can be fully modular, validated, and reusable, and still fail as EPPO content because individual topics depend on a reading order. Conversely, EPPO makes demands (context, qualification, one level) that no schema validation can check automatically.