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About This Book

Welcome from Sage

Welcome, Investigators!

Sage the crane waving welcome Hello — I'm Sage, the crane with the clipboard. This book is your field notebook for understanding the health of whole populations, not just individual patients. Together we'll measure disease, map social determinants, build simulations of epidemics, and pull apart the feedback loops that drive everything from opioid misuse to vaccine uptake. What does the evidence show? That's the question we'll keep coming back to. Let's look at the data together.

Why This Intelligent Textbook

Public health is the discipline that decides whose drinking water gets tested, which outbreaks get investigated, which vaccines reach which neighborhoods, and which misinformation campaigns get countered. The COVID-19 pandemic exposed how fragile that infrastructure is in the United States and globally — and how unprepared most students entering medicine, nursing, social work, and data science are to reason about populations rather than individual patients. This textbook exists to close that gap with a rigorous, systems-thinking, simulation-rich introduction that treats public health as a quantitative discipline grounded in evidence.

In the United States:

  • US life expectancy at birth fell from 78.8 years in 2019 to 76.1 years in 2021 — the steepest two-year decline in roughly a century, driven by COVID-19, drug overdose, and worsening chronic disease1
  • The Bureau of Labor Statistics projects employment of epidemiologists will grow much faster than average through 2032, with similar above-average growth in environmental scientists, health educators, and biostatisticians2
  • The de Beaumont Foundation estimates state and local governmental public health departments need to hire roughly 80,000 additional full-time-equivalent staff to deliver a minimum package of public health services3
  • Only about 12 percent of US adults have proficient health literacy, leaving nearly nine in ten adults who struggle to use everyday health information for self-care, decision-making, or navigating the health system4

Worldwide:

  • The World Health Organization estimates 14.9 million excess deaths were associated with the COVID-19 pandemic globally during 2020 and 2021 — roughly 2.7 times the officially reported COVID-19 death toll over the same period5
  • More than half of the world's population still lacks full coverage of essential health services, and roughly 2 billion people face catastrophic or impoverishing health spending each year6
  • The Sustainable Development Goals call for reducing premature mortality from non-communicable diseases by one-third by 2030 — a target the world is currently not on track to meet7

These numbers represent millions of people — your patients, neighbors, and students — whose lives turn on whether the next generation of public health workers can read evidence carefully, model complex systems honestly, and communicate uncertainty without losing trust. This book exists to prepare them.

This textbook takes a fundamentally different approach from the printed introductory texts that dominate the field. It is built on a validated learning graph of 500 interconnected concepts organized across 16 taxonomy categories — the five CEPH-accredited core domains (epidemiology, biostatistics, environmental health, health policy and management, and social and behavioral health) plus eleven cross-cutting areas including systems thinking, data science, simulation design, health equity, ethics, communication, prevention science, and a deep COVID-19 case study running through every chapter. Concepts are introduced in prerequisite order so understanding builds chapter by chapter. Throughout the book you will find interactive MicroSims — browser-based simulations of SEIR dynamics, causal loop diagrams, healthcare surge capacity, screening test performance, and more — that let students manipulate parameters and discover principles through experimentation rather than memorization. The entire textbook is open source and free under a Creative Commons license — no paywalls, no access codes, no expensive annual editions.

How to Use This Book

This textbook is designed for self-paced study and for use as a primary or supplementary text in introductory public health courses. Each chapter builds on previous material, so reading in order is recommended. The book includes:

  • 20 Chapters covering public health foundations, epidemiology (disease measurement and study design), biostatistics (foundations and regression), environmental health, social and behavioral health, health policy, global health, equity and social determinants, ethics, communication, prevention science, systems thinking (foundations and modeling), data science (foundations and advanced), simulation design, a COVID-19 master case study, and health fraud and misinformation
  • Interactive MicroSims embedded throughout — browser-based simulations you can manipulate to explore SEIR dynamics, causal loop diagrams, screening performance, surge capacity, and more
  • Quizzes at the end of each chapter to test understanding across Bloom's Taxonomy levels
  • Annotated References linking to Wikipedia and authoritative sources including CDC, WHO, NIH, and peer-reviewed publications
  • Glossary with precise, non-circular definitions for every key concept
  • FAQ with common questions from students, instructors, and curriculum staff
  • Learning Graph visualizing how all 500 concepts depend on one another
  • Search available from any page using the search bar in the top right
  • Sage the Crane — a pedagogical mascot who appears in every chapter to introduce key concepts, flag common pitfalls, and celebrate progress

The Learning Graph visualizes how concepts connect across chapters. If you want to explore non-linearly or check prerequisites for a specific topic, start there.

About the Author

Dan McCreary is a semi-retired AI researcher, solution architect, and educator who has spent more than three decades helping Fortune 100 organizations reason over massive datasets. At Optum he founded the Generative AI Center of Excellence and led the team that built one of the world's largest healthcare knowledge graphs — spanning over 25 billion vertices — to unify member, provider, and patient insights. Dan's deep background in knowledge representation, healthcare data, and systems thinking underpins the precise learning graphs and intelligent textbook workflows used throughout this course.

He is the co-author of Making Sense of NoSQL (Manning Publications), the founding chair of the NoSQL Now! conference, and a frequent keynote speaker on semantic search, ontology strategy, and AI hardware. Beyond industry, Dan has mentored students as a STEM volunteer since 2014 and now applies the same rigor to building open educational resources. You can visit the Intelligent Textbooks Case Studies to see over 87 textbooks that Dan has created or co-created with other authors.

Selected Credentials

  • B.A. in Physics and Computer Science from Carleton College
  • M.S.E.E. from the University of Minnesota
  • MBA coursework at the University of St. Thomas
  • Patent holder in semantic search and ontology management techniques
  • Founder of Optum's Generative AI Center of Excellence and architect of a 25-billion-vertex healthcare knowledge graph
  • Advocate for large-scale Enterprise Knowledge Graph adoption across healthcare and education
  • Long-time promoter of accessible, low-cost AI-powered learning experiences

How to Cite This Book

If you reference this textbook in academic work, curriculum proposals, lesson plans, or other publications, please use one of the following citation formats.

APA (7th edition)

McCreary, D. (2026). Introduction to Public Health. https://dmccreary.github.io/public-health/

Chicago (17th edition)

McCreary, Dan. 2026. Introduction to Public Health. https://dmccreary.github.io/public-health/.

MLA (9th edition)

McCreary, Dan. Introduction to Public Health. 2026, dmccreary.github.io/public-health/.

BibTeX

@book{mccreary2026publichealth,
  title     = {Introduction to Public Health},
  author    = {McCreary, Dan},
  year      = {2026},
  url       = {https://dmccreary.github.io/public-health/},
  note      = {Interactive intelligent textbook}
}

To cite a specific chapter, append the chapter number and title — for example:

McCreary, D. (2026). Chapter 1: Foundations of Public Health. In Introduction to Public Health. https://dmccreary.github.io/public-health/chapters/01-foundations/

License

This work is released under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (CC BY-NC-SA 4.0). You are free to share and adapt the material for non-commercial purposes as long as you give appropriate credit and share your adaptations under the same license.

References

  1. Arias, E., Tejada-Vera, B., Kochanek, K. D., & Ahmad, F. B. (2022). Provisional Life Expectancy Estimates for 2021. National Center for Health Statistics, Vital Statistics Rapid Release Report No. 23. https://www.cdc.gov/nchs/data/vsrr/vsrr023.pdf ↩

  2. US Bureau of Labor Statistics. (2024). Occupational Outlook Handbook — Epidemiologists, Environmental Scientists, Health Education Specialists, Statisticians. US Department of Labor. https://www.bls.gov/ooh/life-physical-and-social-science/epidemiologists.htm ↩

  3. de Beaumont Foundation & Public Health National Center for Innovations. (2021). Staffing Up: Workforce Levels Needed to Provide Basic Public Health Services for All Americans. https://debeaumont.org/staffing-up/ ↩

  4. Kutner, M., Greenberg, E., Jin, Y., & Paulsen, C. (2006). The Health Literacy of America's Adults: Results from the 2003 National Assessment of Adult Literacy (NCES 2006–483). US Department of Education, National Center for Education Statistics. (Findings reaffirmed in Healthy People 2030 health-literacy objectives.) https://nces.ed.gov/pubs2006/2006483.pdf ↩

  5. World Health Organization. (2022). 14.9 million excess deaths associated with the COVID-19 pandemic in 2020 and 2021 (News Release, 5 May 2022). https://www.who.int/news/item/05-05-2022-14.9-million-excess-deaths-were-associated-with-the-covid-19-pandemic-in-2020-and-2021 ↩

  6. World Health Organization & World Bank. (2023). Tracking Universal Health Coverage: 2023 Global Monitoring Report. https://www.who.int/publications/i/item/9789240080379 ↩

  7. World Health Organization. (2023). World Health Statistics 2023: Monitoring health for the SDGs. https://www.who.int/publications/i/item/9789240074323 ↩