+The following variables are tweakable:
+
+@table @code
+@item rfc2047-default-charset
+@vindex rfc2047-default-charset
+Characters in this charset should not be decoded by this library.
+This defaults to @code{iso-8859-1}.
+
+@item rfc2047-header-encoding-alist
+@vindex rfc2047-header-encoding-alist
+This is an alist of header / encoding-type pairs. Its main purpose is
+to prevent encoding of certain headers.
+
+The keys can either be header regexps, or @code{t}.
+
+The values can be either @code{nil}, in which case the header(s) in
+question won't be encoded, or @code{mime}, which means that they will be
+encoded.
+
+@item rfc2047-charset-encoding-alist
+@vindex rfc2047-charset-encoding-alist
+RFC2047 specifies two forms of encoding---@code{Q} (a
+Quoted-Printable-like encoding) and @code{B} (base64). This alist
+specifies which charset should use which encoding.
+
+@item rfc2047-encoding-function-alist
+@vindex rfc2047-encoding-function-alist
+This is an alist of encoding / function pairs. The encodings are
+@code{Q}, @code{B} and @code{nil}.
+
+@item rfc2047-q-encoding-alist
+@vindex rfc2047-q-encoding-alist
+The @code{Q} encoding isn't quite the same for all headers. Some
+headers allow a narrower range of characters, and that is what this
+variable is for. It's an alist of header regexps / allowable character
+ranges.
+
+@item rfc2047-encoded-word-regexp
+@vindex rfc2047-encoded-word-regexp
+When decoding words, this library looks for matches to this regexp.
+
+@end table
+
+Those were the variables, and these are this functions:
+
+@table @code
+@item rfc2047-narrow-to-field
+@findex rfc2047-narrow-to-field
+Narrow the buffer to the header on the current line.
+
+@item rfc2047-encode-message-header
+@findex rfc2047-encode-message-header
+Should be called narrowed to the header of a message. Encodes according
+to @code{rfc2047-header-encoding-alist}.
+
+@item rfc2047-encode-region
+@findex rfc2047-encode-region
+Encodes all encodable words in the region specified.
+
+@item rfc2047-encode-string
+@findex rfc2047-encode-string
+Encode a string and return the results.
+
+@item rfc2047-decode-region
+@findex rfc2047-decode-region
+Decode the encoded words in the region.
+
+@item rfc2047-decode-string
+@findex rfc2047-decode-string
+Decode a string and return the results.
+
+@end table
+
+
+@node time-date
+@section time-date
+
+While not really a part of the @acronym{MIME} library, it is convenient to
+document this library here. It deals with parsing @code{Date} headers
+and manipulating time. (Not by using tesseracts, though, I'm sorry to
+say.)
+
+These functions convert between five formats: A date string, an Emacs
+time structure, a decoded time list, a second number, and a day number.
+
+Here's a bunch of time/date/second/day examples: