In GNU Emacs 21.1.1 (i386-debian-linux-gnu, X toolkit, Xaw3d scroll bars) of 2001-12-07 on raven, modified by Debian configured using `configure i386-debian-linux-gnu --prefix=/usr --sharedstatedir=/var/lib --libexecdir=/usr/lib --localstatedir=/var/lib --infodir=/usr/share/info --mandir=/usr/share/man --with-pop=yes --with-x=yes --with-x-toolkit=athena --without-gif' Important settings: value of $LC_ALL: nil value of $LC_COLLATE: nil value of $LC_CTYPE: nil value of $LC_MESSAGES: nil value of $LC_MONETARY: nil value of $LC_NUMERIC: nil value of $LC_TIME: nil value of $LANG: nil locale-coding-system: nil default-enable-multibyte-characters: t When the help-data in info-lookup-alist specifies that symbols are case-sensitive, the index search performed by info-lookup-symbol (C-h C-i) is instead case-insensitive when searching through index entries. I'm not aware of any of the manuals in the supplied info-look.el which have two index entries differing only in case. But I encountered the problem while setting up some sh-mode data. bash.info has a variable "GROUPS", and sh-utils.info has the program "groups". The problem can be illustrated with a contrived foo.info below, having index entries "foo" and "FOO". Put it and the foo.el below in an otherwise empty directory and run emacs -q -no-site-file -l foo.el foo.el sets up foo.info as case-sensitive help for fundamental-mode, and leaves such a buffer with "FOO" and "foo" ready to be looked up with C-h C-i. Press C-h C-i on either "FOO" or "foo" and notice that both bring up the node for lower case "foo", whereas I believe for "FOO" it ought to bring up the upper case FOO node. I think this is just a problem with the searching in info-lookup, since info-lookup-cache records the available index entries in their correct case. In fact I believe the use of Info-menu in info-lookup might be the problem, since it forcibly binds case-fold-search to t. No doubt that's good for interactive use, but it's not what info-lookup wants. I get some joy from the info-lookup.el.diff below, doing a case-sensitive search in the index node to get to the right spot. * info-look.el (info-lookup): Replace Info-menu call with a case sensitive search of the index, to preserve sensitivity requested by the help data. I believe this is correct for case-insensitive help modes too, since the index entries in info-lookup-cache are recorded with their case unchanged, only the symbols to which they refer are downcased.