The Def Leppard discography was originally created by Kathleen Clark in 1989, at the time the official Def Leppard archivist. An official and complete worldwide publication was planned, including records, tapes and CD's (both commercial and promotional); videos (commercial and promotional); radio and TV appearances; printed media (books, magazines, posters, etc.); and guest appearances on non-Def Leppard recordings, among other items. Unfortunately, this publication never materialized.
This current online discography took the basics of Kathleen Clark's original discography, and focuses on albums, CD's, cassettes, videos and DVDs only. Information from various fan-made discographies (the most comprehensive by Tom Erkenswick and Mark Schmidt) were used for additional information about releases between 1979-1996.
Additional research for a lot of these releases was done with the help of Boris Leskovec and David Bason, and hopefully many more people in the future.

Not even close. The software engine/backbone and graphical interface have been finished only recently and I've just started adding the actual discography items to the database. This job will take months, if not years, before it will be completed. And even then, there is a pretty good chance that there are items out there that I don't know about -- these items are obviously not included in this discography.
Items are pretty much being added in chronological order, and I'm currently only at the "HYSTERIA"-era (1987-1988), although the "YEAH!"-era has been finished as well.

No. Sometimes, information is based on hearsay, and there might be a bunch of typos scattered around here and there as well.
Some release dates are definitely not correct, because they are unknown. For items that only have a known year of release, the release date 12/31 will be used. For items that only have a known month and year of release, the last date of that month will be used.

Until a few years ago, US record labels issued catalogue numbers following a certain standard. Usually formed by a 6-digit number that would indicate the actual title, the last number commonly referred to the format of the item:
1 - 12" vinyl (album or single)
2 - CD (album or single)
4 - cassette
7 - 7" vinyl single
For example, the catalogue number of the "HYSTERIA" CD is 830-675-2, the vinyl version is number 830-672-1 and the cassette is 830-675-4.
Please note that this is just a general indication; many items follow different standards. In this discography, catalogue numbers do not have dashes, slashes, periods, spaces, or anything else other than letters and numbers. This is done to make it easier for the (future) search functionality to find items in the database.

Usually, with releases that are numbered, quantities are distributed as follows: 0001-0015 go to the band; 0016-0150 are used for internal promotion; and 0151 and higher are distributed to retail outlets.

This functionality is currently being programmed and will be added when it's done.

Whenever an item has NO "custom" artwork whatsoever (meaning that the cover, label, booklet, or anything else, has generic record label artwork), it will not be included in this discography. Examples of this are the labels that come with vinyl albums (green UFOs for Vertigo, blue/white buildings, black with red/yellow Mercury logo), standard CD labels, or white vinyl single sleeves/labels. Only artwork that is distinctively Def Leppard will be included here (most covers and sleeves, obviously). When a label is generic but there is still something that makes it 'custom' (the inclusion of the Def Leppard logo, a specific album title font, etc.), it is included. When it's NOT included however, it doesn't automatically mean it's all generic -- I might just have missed it, or not have it in my possession.

If you've spotted an error in an item that is already in the database, please write down the Discography item no (a unique ID that is listed with each item) and send me a message with your comments about the item.
If you are in the possession of any items listed that have the "NOT AVAILABLE" graphic, please get it touch -- this means I'm looking for that specific artwork.
If you have an item that's not listed here, please note that at this point, I've only been able to work on items up to 1988, so additions for post-"HYSTERIA" are not needed at this point. For any item you might have that was released before 1988 that should be included in this discography, please get in touch.