Frequently Amazon does not restock books once they have sold all the ones they originally ordered.
If this is indeed the case, then there's a whole bunch of other 4E books which will soon be in the category of "not being available directly from amazon.com".
(Number of copies left as of June 1, 2011 at amazon.com).
- [ame="http://www.amazon.com/Thunderspire-Labyrinth-Dungeons-Dragons-Adventure/dp/0786948728"]H2 Thunderspire Labyrinth (14 copies left)[/ame]
- [ame="http://www.amazon.com/Forgotten-Realms-Campaign-Guide-4th/dp/0786949244"]Forgotten Realms Campaign Guide (18 copies left)[/ame]
- [ame="http://www.amazon.com/Pyramid-Shadows-Dungeons-Dragons-Adventure/dp/078694935X"]H3 Pyramid of Shadows (14 copies left)[/ame]
- [ame="http://www.amazon.com/Scepter-Tower-Spellgard-Forgotten-Adventure/dp/0786949546"]Scepter Tower of Spellgard (9 copies left)[/ame]
- [ame="http://www.amazon.com/King-Trollhaunt-Warrens-Adventure-P1/dp/0786949287"]P1 King of the Trollhaunt Warrens (5 copies left)[/ame]
- [ame="http://www.amazon.com/Draconomicon-Chromatic-Dragons-Rules-Expansion/dp/0786949805"]Draconomicon 1: Chromatic Dragons (6 copies left)[/ame]
- [ame="http://www.amazon.com/Demon-Queens-Enclave-Adventure-Dungeons/dp/0786949775"]P2 Demon Queen's Enclave P2 (1 copy left)[/ame]
- [ame="http://www.amazon.com/Manual-Planes-Supplement-Rules-Expansion/dp/0786950021"]Manual of the Planes (9 copies left)[/ame]
- [ame="http://www.amazon.com/Open-Grave-Secrets-Undead-Supplement/dp/0786950692"]Open Grave: Secrets of the Undead (10 copies left)[/ame]
- [ame="http://www.amazon.com/Assault-Nightwyrm-Fortress-Adventure-4th/dp/0786950005"]P3 Assault on Nightwyrm Fortress (10 copies left)[/ame]
- [ame="http://www.amazon.com/Deaths-Reach-Adventure-E1-4th/dp/0786951028"]E1 Death's Reach (8 copies left)[/ame]
- [ame="http://www.amazon.com/Monster-Manual-Core-Rulebook-Supplement/dp/078695101X"]Monster Manual 2 (6 copies left)[/ame]
- [ame="http://www.amazon.com/Eberron-Players-Guide-4th-Supplement/dp/0786951001"]Eberron Player's Guide (15 copies left)[/ame]
- [ame="http://www.amazon.com/Kingdom-Ghouls-Adventure-Dungeons-Dragons/dp/0786952318"]E2 Kingdom of the Ghouls (13 copies left)[/ame]
- [ame="http://www.amazon.com/Eberron-Campaign-Guide-4th-Supplement/dp/0786950994"]Eberron Campaign Guide (17 copies left)[/ame]
- [ame="http://www.amazon.com/Seekers-Ashen-Crown-Adventure-Eberron/dp/078695017X"]Seekers of the Ashen Crown (11 copies left)[/ame]
- [ame="http://www.amazon.com/Dragon-Magazine-Annual-4th-Compilation/dp/0786952458"]Dragon Magazine Annual, Volume 1 (4 copies left)[/ame]
- [ame="http://www.amazon.com/Dungeon-Masters-Guide-Core-Rulebook/dp/078695244X"]Dungeon Master's Guide 2 (9 copies left)[/ame]
- [ame="http://www.amazon.com/Primal-Power-Supplement-Mike-Mearls/dp/0786950234"]Primal Power (16 copies left)[/ame]
- [ame="http://www.amazon.com/Prince-Undeath-Adventure-Dungeons-Dragons/dp/0786952474"]E3 Prince of Undeath (11 copies left)[/ame]
- [ame="http://www.amazon.com/Draconomicon-Metallic-Dragons-4th-Supplement/dp/0786952482"]Draconomicon 2: Metallic Dragons (11 copies left)[/ame]
- [ame="http://www.amazon.com/Plane-Below-Secrets-Elemental-Supplement/dp/0786952490"]The Plane Below (17 copies left)[/ame]
- [ame="http://www.amazon.com/Underdark-4th-D-Supplement/dp/078695387X"]Underdark (12 copies left)[/ame]
- [ame="http://www.amazon.com/Players-Handbook-Races-Dragonborn-Supplement/dp/0786953861"]Player's Handbook Races: Dragonborn (17 copies left)[/ame]
- [ame="http://www.amazon.com/Martial-Power-Supplement-Richard-Baker/dp/0786953896"]Martial Power 2 (19 copies left)[/ame]
- [ame="http://www.amazon.com/Hammerfast-Dwarven-Outpost-Adventure-Site/dp/0786955341/"]Hammerfast (8 copies left)[/ame]
- [ame="http://www.amazon.com/Players-Handbook-4th-Core-Rulebook/dp/078695390X"]Player's Handbook 3 (20 copies left)[/ame]
- [ame="http://www.amazon.com/Plane-Above-Secrets-Astral-Supplement/dp/0786953926"]The Plane Above (11 copies left)[/ame]
- [ame="http://www.amazon.com/Dungeon-Magazine-Annual-Vol-Compilation/dp/0786952008"]Dungeon Magazine Annual, Volume 1 (7 copies left)[/ame]
- [ame="http://www.amazon.com/Slaying-Stone-Adventure-HS1-4th/dp/0786953888"]HS1 The Slaying Stone (12 copies left)[/ame]
- [ame="http://www.amazon.com/Players-Handbook-Races-Tieflings-4th/dp/0786954892"]Player's Handbook Races: Tieflings (8 copies left)[/ame]
- [ame="http://www.amazon.com/Orcs-Stonefang-Pass-Adventure-HS2/dp/0786953918"]HS2 Orcs of Stonefang Pass (18 copies left)[/ame]
- [ame="http://www.amazon.com/Vor-Rukoth-Ancient-Ruins-Adventure/dp/078695549X"]Vor Rukoth (15 copies left)[/ame]