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:

Domain: Philosophy

Link: History of Philosophy - Summarized & Visualized

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.
• Adams Synchronological Chart (Map of History) [chart] — 23‑ft illustrated timeline spanning 4004 BC → 1881 AD; America’s 19th‑c. “grand synthesis.”

Religion

• 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.
• The Internet Philosophy Ontology project: The Taxonomy [taxonomy] — A nested-list-tree of philosophical ideas.

Literature

• 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.
• What every computer science major should know by Matt Might [syllabus] — List of subjects that CS majors should learn and why.
• AI safety map [chart] — AI safety organization map.

Mathematics

• 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.
• Stalin’s Library: A Dictator and His Books by Geoffrey Roberts [book] — Yale‑published study of Stalin’s marginalia and 25,000-volume personal archive. 

Education

• Open Syllabus: Galaxy [interactive graph] — Database of syllabuses, with usage data.
• syllabi.directory [directory] — Project having experts create syllabi from their fields.
• UT Austin Access Syllabi & CVs [database] — Searchable archive of undergraduate course syllabi and instructor CVs.

Research

• 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.
• Listing of Dharma Retreat Centers and Teachings by Wolf [directory] — Google doc with reviews of meditation retreat locations.
• 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.

Political Science

• Atlas of Live Players & Institutions and Geographical Bismarck Brief by Samo Burja [list, map] — A continuously updated map of power‑wielding individuals and orgs.

By Medium

• The Best Maps of Every Subject by Parker Conley [directory] — Reference works sorted by domain.
• The Best Textbooks on Every Subject by Luke Muehlhauser [directory] — Textbooks vetted by people experienced in a field.
• The Best Tacit Knowledge Videos on Every Subject by Parker Conley [directory] — Tacit knowledge videos vetted by expertise.

Other Lists like This

• Britannica Propaedia [classification system] — Outline of Knowledge volume that structures the entire Encyclopædia Britannica.
• List of lists of lists from Wikipedia [directory] — Wikipedia has lots of lists.
• Outline of outlines from Wikipedia [directory] — And lots of outlines.
• 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.
• UsefulCharts - YouTube [charts] — YouTube channel with charts like these.
• 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.
• 100+ Interesting Data Sets for Statistics by Ryan Smith [curated list] — Pirate Bay logs, global health, Reddit dumps and other real‑world practice sets.

Further Reading

• A Guidebook to Learning: For a Lifelong Pursuit of Wisdom by 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.
• In Praise of Reference Books by Daniel M. Rothschild. Some more thoughts on reference works as a thing.
• “Encyclopaedias in general” by Britannica surveys the encyclopaedia genre, scope, and editorial models.
• Exercises in Comprehensive Information Gathering speaks to the benefits of engaging with fields broadly.
• Big Understanding by Ethan M. Edwards speaks in favor of projects like this.
• Metabibliography.
• How Math Academy Creates its Knowledge Graph by Justin Skycak, on the idea of knowledge graphs.
• Burny’s digital garden.

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.

Also, this post and The Best Tacit Knowledge Videos on Every Subject take time to maintain. If you’d like to help, drop me a line! I'll pay you $2/entry-added.