   DX9
  Don''t mean to sound like a putz, but I don''t want to loose what I have ... If I install the DX9 sdk, will that eliminate my ability to continue to use dx8 & dx7 sdk''s? ... if so, then I would love to just look at the documentation for dx9 sdk without installing it, just to see changes for myself. 
  No, courtesy of COM you can grab an interface to DirectX 7, 8 or 9 through 9. ;  I''ll confirm what Woodsman just said.  I still use DX8 interfaces for coding, even though I have DX9 installed. ;  You may want to grab the DX9 Extras too.  I believe they contain docs for older versions while the main install only has docs for DX9.   Stay Casual,KenDrunken Hyena;  Keep in mind that installing DX9 will permanantly upgrade the system drivers to DX9 and there is no simple way to go back. Yes, you can still compile and run DX 7, 8, and 9 based programs but you may find that they don''t behave exactly the same. Some low level stuff in the new drivers can change the behavior of the old DX versions (even if Microsoft says otherwise). ;  In the vast majority of cases, things will be fine.In some cases, however, upgrading will screw up old versions. More often than not, this is due to something being wrong in your code in the first place, but for some reason it worked in previous versions and then got fixed. Things like undefined values, out of range values, etc.Oh, and I wouldn''t recommend installing all the SDKs in the same directory, as they may or may not happily overwrite each other. 