[Extract from the File Formats FAQ...]

To obtain the IGES specification, you must be a member of both the
National IGES User Group (NIUG) and a Regional Interest Group
(RIG). The IGES specification is available through the NCGA for
$100US. For more information about the NIUG, RIGs, and IGES, contact:

  National Computer Graphics Association
  2722 Merrilee Drive
  Suite 3200
  Fairfax, VA 22031 USA
  Voice: 703.698.9600

[IGES is a set of protocols for the transfer and display of graphical
information on remote devices via a telephone or computer
communications network. IGES does not define any new graphical file
formats, but instead uses existing formats (such as CGM) to
encapsulate graphical data.]