The offline library
Every one of these is free, legal and downloadable today. Take them before you need them — that is the entire point.
Start here: bulk archives
Individual books are useful. These are transformative — mirror them to physical media first, in priority order.
The single highest-value object you can store. One file holds essentially every technical article humanity has written down, readable on a phone with no network. If you take exactly one thing from this page, take this. Take the largest version your storage allows, and take a second copy.
Where There Is No Doctor, Where There Is No Dentist, A Book for Midwives, Helping Children Who Are Deaf. Written specifically for people practising medicine with no hospital, no laboratory and no reliable drug supply — which is exactly your situation. Free digital copies, and the full text is on their HealthWiki.
Thousands of practical village-technology manuals — building, water, food processing, small-scale metalwork, farm tools. The original cd3wd.com is dead. It survives only as mirrors on the Internet Archive, which is the copy you should take.
Peer-reviewed, current, openly licensed university textbooks: algebra through calculus, physics, chemistry, biology, anatomy, microbiology. This is the teaching layer — the thing that turns a surviving group into one that can still produce engineers in generation two.
The current international standard for drinking-water quality and sanitary practice, including the household treatment methods that matter when there is no utility. Freely downloadable from WHO's IRIS repository.
The planning numbers for a camp or a new settlement in one place: ground per person, spacing and firebreaks, latrine and water distances, drainage and site selection. It follows the Sphere humanitarian standards. Save the settlement, shelter and water entries before you need them.
WHO's field guide for health staff: the cold chain, vaccine handling, the shake test, vial monitors, and running a session. The manual behind the rules on the refrigeration step.
Written at the last moment when a general encyclopaedia still explained industrial processes in enough operational detail to follow: how a blast furnace is charged, how a dynamo is wound, how soda ash is made. Modern encyclopaedias describe; this one instructs. The transcribed Wikisource text is far more useful than page scans.
A large collection of pre-1920 practical American technical books, deliberately assembled around the question 'how would you rebuild this without electricity'. Heavy overlap with Gutenberg but includes trade manuals Gutenberg never digitised.
Note: Site root is live; internal index paths move often — navigate from the homepage rather than bookmarking deep links.
The living wiki of appropriate technology: hand pumps, biosand filters, rocket stoves, composting latrines, small-scale biogas. Where CD3WD is a frozen archive, this is maintained. Available as a Kiwix ZIM for offline use.
The world's most complete free library on growing food at every scale — crop agronomy by species and climate, animal husbandry, irrigation, storage, fisheries, post-harvest loss. Gutenberg's agriculture is Victorian; this is current and global.
Soil survey methods, erosion control, crop rotation and the home food preservation guidance that keeps a harvest edible through winter. The USDA canning guide is maintained by NCHFP, not by the USDA page usually cited for it.
Density, strength, drying, decay and fastening of the commercially important woods, measured. The numbers behind choosing a log that floats, a spar that bends without breaking and a plank that will not rot.
The practical manual for safely composting human waste and returning it to soil — closing the nutrient loop that industrial agriculture closes with synthetic fertiliser you will not have for decades.
Free university-level chemistry, physics, engineering and biology, deeper and more specialised than OpenStax. The chemistry library in particular covers the industrial processes in tiers 3–5.
Everything listed individually below, plus 75,000 more. The complete mirror is small enough to be worth taking whole rather than curating — and its pre-1929 technical books describe processes at the workshop scale you will actually be operating at.
The fallback for anything not found elsewhere, including scans of trade manuals, military field manuals and out-of-print engineering texts. Search by subject, download the DjVu/PDF, and store what you use.
Individual titles
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