Probably the most complete collection of Otis King's Patent Calculator (cylindrical slide rule) information on-line.

Dedicated to one man's collection of slide rules (and includes a photo gallery), plus a few links for those who want to find out more about them or where to buy one.

Repository for information, pictures, history and links to sellers, other sites and experts, and an online store.

Slide rule model information, pictures, and history from all over the world.

Presents Napier's Bones and the Genaille Lucas rulers in ready to print forms: Postcript and PDF.

Archives of photos of large personal collection.

Large categorised collection with photos and notes.

Todd Tolhurst describes his collection, some with pictures.

Site for Jay Francis, a collector of slide rules and antique mechanical calculators. Items for sale or trade, and many related links.

Online sales and swap meet. Private individuals only.