Chris Osburn's Calculating Instruments
- Classifies and lists slide rule and scales. Grouped by type, size, country of origin and manufacturer. Articles, a discussion forum and a section on buying and selling.
- http://sliderule.mraiow.com/

Slide Rule Museum
- Dedicated to engineers past and present, this collection of slide rules and manuals have in excess of 1000 different items scanned full size and categorized by company or continent. Also offers a comprehensive glossary of slide rule terms and links.
- http://www.sliderulemuseum.com/

Technical Collectibles
- Slide rules and planimeters for sale.
- http://www.technicalcollectibles.com/Slide%20Rules/slide_rule.htm

Giovanni Breda's Slide Rule Collection
- Giovanni Breda shows his collection. A sheet for each rule is provided including high resolution images. Links to other collector's site are also provided.
- http://www.sliderule.it

IM2001 - 7th International Meeting for Slide Rule and Calculating Machine Collectors
- Munich, Germany, September 14 - 16, 2001.
- http://www.rechenschieber.org/

Peter Owen, Collector of Slide Rules
- Texts and photographs.
- http://homepages.tesco.net/physics/

Slide Rule Trade Offer
- An offer to trade kite aerial photographs for slide rules.
- http://www.arch.ced.berkeley.edu/kap/background/kapoffer.html

Napier's Bones and the Genaille-Lucas Rulers
- Presents Napier's Bones and the Genaille Lucas rulers in ready to print forms: Postcript and PDF.
- http://www.nmt.edu/~borchers/napier/napier.html

HP Museum - Early Calculators
- Some non-HP calculators that were introduced anywhere from centuries ago to the late 60's.
- http://www.hpmuseum.org/prehp.htm

Slide Rules
- 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.
- http://www.eyrie.org/~dvandom/slide/index.html

The Death of the Slide Rule
- Hyperlinked essay with citations by James Redin covering the rise of the portable calculator and the demise of its predecessor.
- http://www.dotpoint.com/xnumber/hp.htm

Otis King's Patent Calculator
- Probably the most complete collection of Otis King's Patent Calculator (cylindrical slide rule) information on-line.
- http://www.svpal.org/~dickel/OK/OtisKing.html

The Slide Rules
- A hyperlinked history of slide rules, details of the author's personal collection, and contact information.
- http://www.giovannipastore.it/index_english.htm

Slide Rules from German Manufacturers
- A collection of slide rules, with descriptions and pictures. Also, some links to other slide rule sites.
- http://www.gaehrken.de/sr/index-e.html

Space Race Slide Rules
- Features some slide rules used in early American and Soviet space programs.
- http://www.nasm.si.edu/galleries/gal114/SpaceRace/sec300/sec320.htm

Model Aircraft Performance Slide Rule Calculator
- Custom slide rule for sale. Online calculations which cover the same functions available on the site. Manual included with the slide rule.
- http://pages.sbcglobal.net/limeybob/

The Sphere Research Slide Rule Archives
- Slide rule model information, pictures, and history from all over the world.
- http://www.sphere.bc.ca/test/2archives.html

Sphere Research's Learning about Slide Rules Site
- Repository for information, pictures, history and links to sellers, other sites and experts, and an online store.
- http://www.sphere.bc.ca/test/2learning.html

The Slide Rule Guy
- Site for Jay Francis, a collector of slide rules and antique mechanical calculators. Items for sale or trade, and many related links.
- http://www.slideruleguy.com/

Peter Holland's Slide Rules
- In German and English. Items for trade with descriptions of condition.
- http://www.peterholland.de/

Discovering Slide Rules
- Relates a story about how one person found a giant cache of new-in-box slide rules.
- http://www.sphere.bc.ca/test/discover.html

Slide Rule Collection
- Todd Tolhurst describes his collection, some with pictures.
- http://www.toddtolhurst.com/sliderules/index.html

The Oughtred Society
- Membership group dedicated to the history and collection of slide rules.
- http://www.oughtred.org/

Slide Rules and Calculators
- Images grouped by type.
- http://chris.gillings.com/collect/slide/index.html

SlideRule Trading Group
- Private trading for members of the group.
- http://groups.yahoo.com/group/sliderule-trade/

House of Slide Rules
- Large categorised collection with photos and notes.
- http://foraker.research.att.com/~davek/slide/

Sphere Research's Slide Rule Universe
- Online sales and swap meet. Private individuals only.
- http://www.sphere.bc.ca/test/swap.html

The International Slide Rule Group at Yahoo!
- A community of slide rule enthusiasts. Several hundred posts a month.
- http://groups.yahoo.com/group/sliderule/

Slide Rule Universe
- Extensive on line archive of slide rule information, plus a catalog of available rules.
- http://www.sphere.bc.ca/test/sruniverse.html

Slide Rule Instructions and Prices.
- Instructions on use of slide rules, and a guide to the price of slide rules.
- http://www.sliderules.clara.net/

David Crate's Slide Rules
- Assorted slide rules for sale as well as some historical information.
- http://www.amug.org/~puppy/

Eric Marcotte, a Slide Rule Collector
- A personal compilation of information on slide rules with much information on his own collection.
- http://www.sliderule.ca/