This is a practical references section, not a formal academic bibliography. It is meant for ordinary readers of this book.
The priorities here are:
If you want one rule of thumb, use free websites first for orientation, then move to books when you want depth.
MacTutor History of Mathematics Archive
The single best free starting point for this book. It is run by the University of St Andrews and is excellent for biographies, topic essays, and quick historical orientation.
Stanford Encyclopedia of Philosophy
Best for the later chapters where mathematics meets philosophy and logic: infinity, set theory, foundations, and Gödel.
Einstein Online
A clear, free, reliable relativity resource produced by the Max Planck Institute for Gravitational Physics and related institutions.
Project Gutenberg
Best place to find free public-domain mathematical classics in readable formats.
Open Library
Useful for checking whether a book is previewable, borrowable, or easy to locate in libraries and used-book markets.
These are the best free starting points for Chapters 1-4. MacTutor is especially good on the ancient material because it combines biography, topic essays, and historical context in one place.
For Chapters 5-7, this is the most realistic free route. It is not a substitute for serious books on Indian mathematics, but it is much more accessible than journal literature and far better than random web summaries.
Cardano’s Ars Magna on Open Library
If the exact edition page changes, searching Open Library for “Ars Magna Cardano” will usually find it quickly.
Project Gutenberg: Euclid
Still useful in the Renaissance chapters because so much early modern mathematics is written in conversation with Euclid.
MacTutor biographies and essays
Best free general source for Tartaglia, Cardano, Newton, Leibniz, Euler, Gauss, Riemann, Cantor, Hilbert, and Gödel.
These are especially useful for Chapters 14 and 16, where ordinary popular summaries often become unreliable.
For Chapter 15, Einstein Online is the best free explanatory resource, and Project Gutenberg gives you the classic texts themselves.
If you want a realistic short shelf for this manuscript, start here:
Carl B. Boyer and Uta C. Merzbach, A History of Mathematics (Open Library)
Still one of the best one-volume overviews of the field.
Victor J. Katz, A History of Mathematics: An Introduction (Open Library)
Broader and often more teachable than Boyer for modern readers.
George Gheverghese Joseph, The Crest of the Peacock (Open Library)
Essential if you want a less Eurocentric history.
Kim Plofker, Mathematics in India (Open Library)
The most important book for the Indian chapters.
If you read only those four, you will already be on much firmer ground than most readers of popular histories of mathematics.
Peter L. Bernstein, Against the Gods (Open Library)
Excellent for the human story behind risk, probability, and finance.
Stephen M. Stigler, The History of Statistics (Open Library)
More serious, but still readable and extremely useful.
These are not always easy, but they are real sources rather than second-hand summaries:
For most earlier material in India, the Islamic world, and Kerala, good free primary texts are harder to find in reader-friendly editions. In those cases, the most realistic path is: MacTutor first, then Open Library, then specialist books if you want to go deeper.
If you want to follow up this book without disappearing into academic papers, this is the best order:
That is enough for most readers. It keeps the references section genuinely usable while still pointing toward serious material.