Microsoft Internet Explorer 4 (IE4) is the fourth version of the Internet Explorer graphical web browser that Microsoft unveiled in Spring of 1997, and released on September 22, 1997, primarily for Microsoft Windows, but also with versions available for the classic Mac OS, Solaris, and HP-UX and marketed as "The Web the Way You Want It".
It was one of the main participants of the first browser war. Its distribution methods and Windows integration were involved in the United States v. Microsoft Corp. case. It was superseded by Microsoft Internet Explorer 5 in March 1999. In addition the Internet Explorer layout engine MSHTML (Trident) was introduced. It attained just over 60% market share by March 1999 when IE5 was released.