Update, 2026-05-01: I will no longer be updating this article as I now think the best way to find reference works is to ask LLMs. Specifically, I recommend you copy-pasting (Ctrl + A, Ctrl + C) this entire page into an LLM and ask for further reference works on X subject.
Reference works provide an overview of a subject. Types of reference works include charts, maps, encyclopedias, glossaries, wikis, classification systems, taxonomies, syllabi, and bibliographies.
Reference works are valuable for orienting oneself to fields, particularly when beginning. They can help identify unknown unknowns; they help get a sense of the bigger picture; they are also very interesting and fun to explore.
It is more difficult to assess the epistemics of reference works than tacit knowledge videos and textbooks due to the breadth of the category “reference work”. That being the case, reference works are selected and included based on my judgment. The key question I intend to answer in selecting reference works is: “Does this reference work feel useful and interesting for giving me orientation in a domain?”
If you know of any reference works, I warmly invite you to submit them in the LessWrong comments with the following structure:
Author(s): Deniz Cem Önduygu, Hüseyin Kuşçu, and Eser Aygün
Type: Interactive Chart
Why: Cool, comprehensive, interactive chart that shows the history of philosophy along a diagonal line.
The List
Humanities
History
Histography by Matan Stauber [interactive timeline] — Wikipedia‑driven interface plotting 14 billion years of events; scale toggles from decades to geological eras and updates daily.
Timeline of World History Poster by UsefulCharts [chart] — wall chart aligning all major civilizations 3300 BCE – present with consciously reduced Euro‑centric bias.
Timeline of US History Poster by UsefulCharts [chart] — 2025 update spans colonial era to today; features two overview maps plus photos of all 47 presidents, color‑coded by party.
Technology over the long run by Max Roser [chart] — Interactive spiral and linear timelines tracing 3.4 million years of technological milestones to illustrate accelerating change.
HyperHistory Online by Andreas Nothiger [interactive timeline] — “Synchronoptic” lifelines, timelines, and maps condensing 3,000 years of world history into a single navigable view.
World Religions Family Tree Poster by UsefulCharts [chart] — 4,000 years of Buddhist, Hindu, Chinese, Jewish, Christian, Islamic, and other lineages on a single branching timeline.
Philosophy
History of Philosophy by Deniz Cem Önduygu, Hüseyin Kuşçu, and Eser Aygün [interactive chart] — Cool, comprehensive, interactive chart that shows the history of philosophy along a diagonal line.
Great English Literature by Henry Oliver [syllabus] — Canon‑focused roadmap from Homer to Hilary Mantel, outlining genre taxonomy, foundational works, and anthologies.
Formal Sciences
Computer Science
Teach Yourself Computer Science by Oz Nova and Myles Bryne [syllabus] — Computer science textbooks and resources from people who have credibly curated computer science resources.
The Princeton Companion to Mathematics by Timothy Gowers (ed.) [reference book] — 1034‑page 2008 encyclopedia of modern mathematics: 133 expert contributors survey key concepts, research fields, famous problems, history, and applications; winner of the 2011 Euler Book Prize.
Timeline of Mathematics by Mathigon (Philipp Legner) [interactive timeline] — Zoomable scroll tracing 20,000 BCE to present with 200 + mathematicians, discoveries, and artefacts, each linked to bite‑size bios and context.
Natural Sciences
Physics
Landmark Numbers by Miles Kodama [list] — Order‑of‑magnitude figures (Earth radius, US population, etc.) for mental estimation.
Earth Science
Water Librarians’ Home Page by Robert Teeter [directory] — Since 1996, a curated link hub for water‑science librarians: agencies, utilities, catalogs, publishers, associations.
Astronomy
Johnston’s Archive by Wm. Robert Johnston [directory] — Independent trove on astronomy, nukes, terrorism, casualty stats, and more.
Professional and Applied Sciences
Library and Information Sciences
UDC Consortium (paywalled, but here’s a summary version) [classification system] — Interactable knowledge classification system.
List of academic fields from Wikipedia [glossary] — Wikipedia article sorting knowledge by academic field.
Fields of Knowledge by Things Made Thinkable [interactive chart] — Zoomable map of Wikipedia’s academic fields.
Connected Papers [interactive chart] — Tool that helps navigate paper references using a tree of nodes.
Gap Map by Convergent Research [interactive map] — Visual catalogue of “fundamental‑development” R&D gaps, needed capabilities and resources.
SpringerLink Journals A‑Z [journal index] — Alphabetical browser for 10M+ Springer Nature articles and 3,000 titles.
Finance
Economic Sectors by TradingView [classification system] — Clickable of all economic sectors and industries in the U.S.
Stock Heatmap by TradingView [interactive chart] — Heatmap of public company stocks sorted by industry.
Medicine and Health
Drugs@FDA Databases [database] — Official queries for Drug Approvals, Orange Book, NDC codes, guides, and post‑marketing data.
Improving Clinical Trial Design by Saloni Dattani [syllabus] — Crash‑course + deep‑dive readings on RCT history, regulation, platform/adaptive designs, and statistical power for faster, cheaper drug discovery.
Meditation
Places To Meditate by Peter Stuckings [directory] — Blog rating meditation retreat locations, mostly in Asia.
Suggested Retreat Locations by Contemplative Studies at Brown University [directory] — Meditation retreat locations recommended by Brown’s program.
Urban Planning
Cities by Devon Zuegel [syllabus] — Urbanism primer spanning agglomeration economics, planning ideologies, and new‑city experiments, with walking‑tour heuristics and essential texts.
Housing Supply by Sam Bowman, Ben Southwood, and John Myers [syllabus] — Evidence‑packed guide to YIMBY economics: supply‑demand fundamentals, “housing theory of everything,” NIMBY politics, and global case studies.
Forecasting
Map of the Prediction Market & Forecasting Ecosystem by Saul Munn [directory] — Reasonably comprehensive mapping of the prediction market/forecasting ecosystem, including prediction markets, forecasting platforms, research/consultancy firms, tools, resources for learning, community infrastructure, and media/news/journalism.
Social Sciences
Economics
EconGraphs [glossary] — A bunch of economics graphs like supply and demand, production possibilities frontier, etc.
List of Lists of Concepts by Romeo Stevens [taxonomy] — IIRC, Romeo Stevens categorized all the frameworks that arose in his mind for a week or two in this document.
Overlooked Links by Collisteru [directory] — Valuable links that search engines don’t typically reach.
Links to interesting things online by Logan Graves [directory] — More interesting links that search engines don’t necessarily capture, similar to Collisteru’s.
Recommended by Gavin Leech [directory] — A bunch of things Gavin Leech recommends.
A Guidebook to Learning: For a Lifelong Pursuit of Wisdomby Mortimer J. Adler. outlines the history of knowledge classification schema and gives advice for being a lifelong learner (with knowledge classification schema in mind).
I often use my keyword map LLM prompt to achieve a similar feeling of orientation to new domains.
Thanks to Saul Munn and Collisteru for conversations that inspired this post. Thanks to Skyler Crossman and nomagicpill for helpful feedback on this post. Thanks to ChatGPT o3 for helping me generate descriptions for some of these links and Claude for helping me rewrite some sentences.
Update, 2026-05-01: I will no longer be updating this article as I now think the best way to find reference works is to ask LLMs. Specifically, I recommend you copy-pasting (Ctrl + A, Ctrl + C) this entire page into an LLM and ask for further reference works on X subject.
Introduction
The Best Textbooks on Every Subject is the Schelling point for the best textbooks on every subject. My The Best Tacit Knowledge Videos on Every Subject is the Schelling point for the best tacit knowledge videos on every subject. This post is the Schelling point for the best reference works for every subject.
Reference works provide an overview of a subject. Types of reference works include charts, maps, encyclopedias, glossaries, wikis, classification systems, taxonomies, syllabi, and bibliographies.
Reference works are valuable for orienting oneself to fields, particularly when beginning. They can help identify unknown unknowns; they help get a sense of the bigger picture; they are also very interesting and fun to explore.
How to Submit
My previous The Best Tacit Knowledge Videos on Every Subject uses author credentials to assess the epistemics of submissions. The Best Textbooks on Every Subject requires submissions to be from someone who has read at least three textbooks in the textbook domain.
It is more difficult to assess the epistemics of reference works than tacit knowledge videos and textbooks due to the breadth of the category “reference work”. That being the case, reference works are selected and included based on my judgment. The key question I intend to answer in selecting reference works is: “Does this reference work feel useful and interesting for giving me orientation in a domain?”
If you know of any reference works, I warmly invite you to submit them in the LessWrong comments with the following structure:
The List
Humanities
History
Religion
Philosophy
Literature
Formal Sciences
Computer Science
Mathematics
Natural Sciences
Physics
Earth Science
Astronomy
Professional and Applied Sciences
Library and Information Sciences
Education
Research
Finance
Medicine and Health
Meditation
Urban Planning
Forecasting
Social Sciences
Economics
Political Science
By Medium
Other Lists like This
Further Reading
Thanks to Saul Munn and Collisteru for conversations that inspired this post. Thanks to Skyler Crossman and nomagicpill for helpful feedback on this post. Thanks to ChatGPT o3 for helping me generate descriptions for some of these links and Claude for helping me rewrite some sentences.