The Cipher LibrarianPAUL CLARK

Author · Librarian · Cryptography educator

Every secret
has a story.

Paul Clark — The Cipher Librarian

Exploring cryptography, from historical ciphers to post-quantum security.

Discover the book Meet Paul
On the reading desk№ 01
Secrets of the Cipher Museum by Paul ‘The Cipher Librarian’ Clark. Gold lettering above a cipher wheel, a torn letter, and a red wax seal.
Secrets of the Cipher MuseumA forthcoming book by Paul Clark
01 Read the stories02 Try the ideas03 Follow the evidence

Books by Paul Clark

The bookshelf.

For readers who want to know
what lies behind the message.

Secrets of the Cipher Museum by Paul ‘The Cipher Librarian’ Clark. Gold lettering above a cipher wheel, a torn letter, and a red wax seal.

Forthcoming · Narrative history

Secrets of the
Cipher Museum

Stories of Hidden Messages
and the People Behind Them

A queen’s letters. A wartime telegram. A message that gives up its words but keeps its author’s identity. Twenty investigations into the people and consequences behind hidden messages.

Step inside the book
20
investigations through history
For the curious
No mathematical background needed
Read, then explore
A free interactive museum alongside the book
An open-ended collection

A home for this book and the ones still to come. New titles and publication news will be shared here as they are ready.

Browse the bookshelf

Beyond the printed page

The last page is
a beginning.

Read about an idea. Try it yourself.
Then ask what the result really tells you.

01 / THE HISTORY

A museum you can enter

Cipher Museum

Explore secret writing, historical codebreaking, and the people behind the discoveries. Follow an exhibit and try an idea for yourself.

Visit the free museum
02 / THE EXPERIMENTS

An idea you can test

Crypto Lab

Experiment with encryption, signatures, privacy, and post-quantum cryptography through browser-based teaching demonstrations.

Explore the free labs

Both projects are free to explore. Teaching examples explain their assumptions and limits.

From the author’s desk

Paul ClarkLibrarianship · Technology · Public service

The person behind the pages

A librarian’s curiosity.
A life of service.

I’m Paul Clark. After three decades in library technology, I’m still drawn to the same question: how can we make difficult ideas useful and accessible to the people who need them?

My books, Cipher Museum, and Crypto Lab bring that question to cryptography—with attention to the sources, space to experiment, and care for the people behind the systems.

More about Paul

A conversation starts here

Keep the curiosity
going.

Questions about the book? An idea for a library program, a reading group, or a collaboration? I’d be glad to hear from you.

Write to Paul paul@systemslibrarian.dev