The science under the product.

Free guides that explain a technology from first principles, for the people who build products on it. Molecular biology, cell analysis, computing and medical devices, to start.

FIRST PRINCIPLES MOLECULAR BIOLOGY MEDICAL DEVICES FREE, NO SIGN-UP

1 · Featured card

GUIDE · DEVICE SOFTWARE AND AINEW

The next patient, the next update.

The central question

Software can never be tested on every path, and an AI model learns only from the data its makers chose. What evidence shows either will give the right answer for the next patient, and what keeps that true after an update?

Why software cannot be tested on every path, IEC 62304 with agile teams and pipelines, SOUP, OTS and the SBOM, how an AI model is trained, scored and watched, what a hospital must check before the first patient, cybersecurity, and what the FDA, the EU and India ask for before and after an update.

Chapters
29
Plates
58
Reading time
≈ 2 h 55 min
Current to
Oct 2026
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Free to read online. No sign-up.

GUIDE · IMMUNOASSAYS

A few molecules in a drop.

The central question

How little of one protein can a test find in a drop of blood, and what sets that floor: the antibody, the label, or the instrument that reads it?

Antibodies and binding, absorbance, chemiluminescence, time-resolved fluorescence and electrochemiluminescence, the automated analyzer as an engineered system, lateral flow and its readers, single-molecule assays, reading a result, and the evidence a reagent and its analyzer need in the US, the EU, India and for WHO prequalification.

Chapters
26
Plates
58
Reading time
≈ 2 h 45 min
Current to
Oct 2026
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Free to read online. No sign-up.

GUIDE · QUANTUM COMPUTING

The price of a right answer.

The central question

What does it cost to get one reliable answer from a quantum computer, and for which problems is that answer worth the cost?

Qubits as arrows, interference, Grover and Shor worked by hand, which problems speed up, noise and error correction, the refrigerator and the signal chain of a qubit, the companies and the results of 2025 and 2026, and the bill for RSA-2048.

Chapters
22
Plates
61
Reading time
≈ 2 h 40 min
Current to
Oct 2026
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Free to read online. No sign-up.

GUIDE · FLOW CYTOMETRY

Particle, signal, number.

The central question

A flow cytometer records flashes of light from particles that cross a laser one at a time. How can those flashes tell one kind of cell from another, how small a particle can they reveal, and when can their count be trusted as a test result?

Fluorescence and scatter, fluidics, lasers, detectors and pulses, compensation and gating, the cytometer as an engineered system, measuring vesicles below the wavelength of light, and what a clinical cytometry test must show in the US, the EU and India.

Chapters
24
Plates
67
Reading time
≈ 2 h 45 min
Current to
Oct 2026
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Free to read online. No sign-up.

GUIDE · PCR

Copy and count.

The central question

A PCR instrument does little more than heat and cool a tube on a schedule. So how does it find one sequence among billions, copy it a billion times, and tell you how much was there?

The chemistry of the cycle, the thermal cycler and its optics, counting by Ct and by digital partitions, the instrument as an engineered system, and the validation and regulation a PCR test must pass in the US, the EU and India.

Chapters
24
Plates
62
Reading time
≈ 2 h 40 min
Current to
Oct 2026
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Free to read online. No sign-up.

GUIDE · SURGICAL ENERGY

Where the heat goes.

The central question

Almost every surgical energy device does one thing to tissue: it raises the temperature for a controlled time. So why does surgery need eleven different energies, and what does it take to put that effect exactly where the surgeon intends, and nowhere else?

The physics of energy in tissue, every surgical energy from monopolar RF to histotripsy, the generators that drive them, the hazards around them, and the testing and regulation a device must pass in the US, the EU and India.

Chapters
23
Plates
62
Reading time
≈ 2 h 15 min
Current to
Sep 2026
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Free to read online. No sign-up.

GUIDE 01 · OMICS

One code, many states.

The central question

Every cell in your body carries the same genome. So what does each omics layer measure that the genome alone cannot?

Every omics layer and how it is measured, from the central dogma to reading a real result, and what it takes for a molecular signature to become a test in the US, the EU and India.

Chapters
20
Plates
36
Reading time
≈ 1 h 50 min
Current to
Sep 2026
Read the guide online→ Get the PDF

Free to read online. No sign-up.

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02 — THE LIBRARY

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Each one starts from first principles and ends where products are built. New titles appear here as they are finished.

03 — HOW WE WRITE THEM

One question.
Every claim sourced.

  1. One central question

    Each guide is built around one question, and every chapter answers part of it.

  2. First principles

    Mechanism before method, starting from school-level science.

  3. Sourced

    Claims are cited to primary papers, guidelines and regulator documents.

  4. Dated

    Each one states the month it is current to, so you know what it could not have known.

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