diff --git a/lib/net/imap.rb b/lib/net/imap.rb
index 4e689b3e..19d5714d 100644
--- a/lib/net/imap.rb
+++ b/lib/net/imap.rb
@@ -154,6 +154,204 @@ module Net
# between UTF-8 and UTF-16), and Net::IMAP::ResponseParseError is
# thrown if a server response is non-parseable.
#
+ # == What's here?
+ #
+ # * {Connection control}[rdoc-ref:Net::IMAP@Connection+control+methods]
+ # * {Core IMAP commands}[rdoc-ref:Net::IMAP@Core+IMAP+commands]
+ # * {...in any state}[rdoc-ref:Net::IMAP@IMAP+commands+for+any+state]
+ # * {...in "not authenticated" state}[rdoc-ref:Net::IMAP@IMAP+commands+for+the+-22Not+Authenticated-22+state]
+ # * {...in "authenticated" state}[rdoc-ref:Net::IMAP@IMAP+commands+for+the+-22Authenticated-22+state]
+ # * {...in "selected" state}[rdoc-ref:Net::IMAP@IMAP+commands+for+the+-22Selected-22+state]
+ # * {...in "logout" state}[rdoc-ref:Net::IMAP@IMAP+commands+for+the+-22Logout-22+state]
+ # * {IMAP extensions}[rdoc-ref:Net::IMAP@Supported+IMAP+extensions]
+ # * {Handling server responses}[rdoc-ref:Net::IMAP@Handling+server+responses]
+ #
+ # === Connection control methods
+ #
+ # - Net::IMAP.new: A new client connects immediately and waits for a
+ # successful server greeting before returning the new client object.
+ # - #starttls: Asks the server to upgrade a clear-text connection to use TLS.
+ # - #logout: Tells the server to end the session. Enters the "_logout_" state.
+ # - #disconnect: Disconnects the connection (without sending #logout first).
+ # - #disconnected?: True if the connection has been closed.
+ #
+ # === Core \IMAP commands
+ #
+ # The following commands are defined either by
+ # the [IMAP4rev1[https://tools.ietf.org/html/rfc3501]] base specification, or
+ # by one of the following extensions:
+ # [IDLE[https://tools.ietf.org/html/rfc2177]],
+ # [NAMESPACE[https://tools.ietf.org/html/rfc2342]],
+ # [UNSELECT[https://tools.ietf.org/html/rfc3691]],
+ #--
+ # TODO: [ENABLE[https://tools.ietf.org/html/rfc5161]],
+ # TODO: [LIST-EXTENDED[https://tools.ietf.org/html/rfc5258]],
+ # TODO: [LIST-STATUS[https://tools.ietf.org/html/rfc5819]],
+ #++
+ # [MOVE[https://tools.ietf.org/html/rfc6851]].
+ # These extensions are widely supported by modern IMAP4rev1 servers and have
+ # all been integrated into [IMAP4rev2[https://tools.ietf.org/html/rfc9051]].
+ # Note: Net::IMAP doesn't fully support IMAP4rev2 yet.
+ #
+ #--
+ # TODO: When IMAP4rev2 is supported, add the following to the each of the
+ # appropriate commands below.
+ # Note:: CHECK has been removed from IMAP4rev2.
+ # Note:: LSUB is obsoleted by +LIST-EXTENDED and has been removed from IMAP4rev2.
+ # Some arguments require the +LIST-EXTENDED+ or +IMAP4rev2+ capability.
+ # Requires either the +ENABLE+ or +IMAP4rev2+ capability.
+ # Requires either the +NAMESPACE+ or +IMAP4rev2+ capability.
+ # Requires either the +IDLE+ or +IMAP4rev2+ capability.
+ # Requires either the +UNSELECT+ or +IMAP4rev2+ capability.
+ # Requires either the +UIDPLUS+ or +IMAP4rev2+ capability.
+ # Requires either the +MOVE+ or +IMAP4rev2+ capability.
+ #++
+ #
+ # ==== \IMAP commands for any state
+ #
+ # - #capability: Returns the server's capabilities as an array of strings.
+ #
+ # Capabilities may change after #starttls, #authenticate, or #login
+ # and cached capabilities must be reloaded.
+ # - #noop: Allows the server to send unsolicited untagged #responses.
+ # - #logout: Tells the server to end the session. Enters the "_logout_" state.
+ #
+ # ==== \IMAP commands for the "Not Authenticated" state
+ #
+ # In addition to the universal commands, the following commands are valid in
+ # the "not authenticated" state:
+ #
+ # - #starttls: Upgrades a clear-text connection to use TLS.
+ #
+ # Requires the +STARTTLS+ capability.
+ # - #authenticate: Identifies the client to the server using a {SASL
+ # mechanism}[https://www.iana.org/assignments/sasl-mechanisms/sasl-mechanisms.xhtml].
+ # Enters the "_authenticated_" state.
+ #
+ # Requires the AUTH=#{mechanism} capability for the chosen
+ # mechanism.
+ #
+ # The +LOGINDISABLED+ capability must NOT be listed.
+ # - #login: Identifies the client to the server using a simple plain text
+ # username and password. Only use as a last resort (after attempting and
+ # failing with #authenticate). Enters the "_authenticated_" state.
+ #
+ # The +LOGINDISABLED+ capability must NOT be listed.
+ #
+ # ==== \IMAP commands for the "Authenticated" state
+ #
+ # In addition to the universal commands, the following commands are valid in
+ # the "_authenticated_" state:
+ #
+ #--
+ # - #enable: Not implemented by Net::IMAP, yet.
+ #
+ # Requires the +ENABLE+ capability.
+ #++
+ # - #select: Open a mailbox and enter the "_selected_" state.
+ # - #examine: Open a mailbox read-only, and enter the "_selected_" state.
+ # - #create: Creates a new mailbox.
+ # - #delete: Permanently remove a mailbox.
+ # - #rename: Change the name of a mailbox.
+ # - #subscribe: Adds a mailbox to the "subscribed" set.
+ # - #unsubscribe: Removes a mailbox from the "subscribed" set.
+ # - #list: Returns names and attributes of mailboxes matching a given pattern.
+ # - #namespace: Returns the namespaces for personal mailboxes, other users'
+ # mailboxes, and shared mailboxes, with the prefixes and path delimiters
+ # used for the mailbox names within each namespace.
+ #
+ # Requires the +NAMESPACE+ capability.
+ # - #status: Returns mailbox information, e.g. message count, unseen message
+ # count, +UIDVALIDITY+ and +UIDNEXT+.
+ # - #append: Appends a message to the end of a mailbox.
+ # - #idle: Allows the server to send updates to the client, without the client
+ # needing to poll using #noop.
+ #
+ # Requires the +IDLE+ capability.
+ # - #lsub: Lists mailboxes the user has declared "active" or "subscribed".
+ #
+ # ==== \IMAP commands for the "Selected" state
+ #
+ # In addition to the universal commands and the "authenticated" commands, the
+ # following commands are valid in the "_selected_" state:
+ #
+ # - #close: Closes the mailbox and returns to the "_authenticated_" state.
+ # Messages with the Deleted flag are permanently removed, unless the mailbox
+ # was opened as read-only.
+ # - #unselect: Closes the mailbox and returns to the "_authenticated_" state,
+ # without expunging any messages.
+ #
+ # Requires the +UNSELECT+ capability.
+ # - #expunge: Permanently removes messages which have the Deleted flag set.
+ # - #uid_expunge: Restricts #expunge to only remove the specified UIDs.
+ #
+ # Requires the +UIDPLUS+ capability.
+ # - #search, #uid_search: Returns sequence numbers or UIDs of messages that
+ # match the given searching criteria.
+ # - #fetch, #uid_fetch: Returns data associated with a set of messages,
+ # specified by sequence number or UID.
+ # - #store, #uid_store: Alters a message's flags.
+ # - #copy, #uid_copy: Copies the specified messages to the end of the
+ # specified destination mailbox.
+ # - #move, #uid_move: Moves the specified messages to the end of the
+ # specified destination mailbox, expunging them from the current mailbox.
+ #
+ # Requires the +MOVE+ capability.
+ # - #check: Mostly obsolete. Can be replaced with #noop or #idle.
+ #
+ # ==== \IMAP commands for the "Logout" state
+ #
+ # No \IMAP commands are valid in the +logout+ state. If the socket is still
+ # open, Net::IMAP will close it after receiving server confirmation.
+ # Exceptions will be raised by \IMAP commands that have already started and
+ # are waiting for a response, as well as any that are called after logout.
+ #
+ # === Supported \IMAP extensions
+ #
+ # ==== +IMAP4rev2+ [RFC9051[https://tools.ietf.org/html/rfc9051]]
+ #
+ # Although IMAP4rev2[https://tools.ietf.org/html/rfc9051] is not supported
+ # yet, Net::IMAP supports several extensions that have been folded into
+ # it: +IDLE+, +MOVE+, +NAMESPACE+, +UIDPLUS+, and +UNSELECT+.
+ #--
+ # TODO: +ENABLE+, +LIST-EXTENDED+, +LIST-STATUS+
+ #++
+ # Commands for these extensions are included with the {Core IMAP
+ # commands}[rdoc-ref:Net::IMAP@Core+IMAP+commands], above. Other supported
+ # extensons are listed below.
+ #
+ # ==== +ID+ [RFC2971[https://tools.ietf.org/html/rfc2971]]
+ # - #id: exchanges client and server implementation information.
+ # ==== +QUOTA+ [RFC2087[https://tools.ietf.org/html/rfc2087]]
+ # - #getquota: returns the resource usage and limits for a quota root
+ # - #getquotaroot: returns the list of quota roots for a mailbox, as well as
+ # their resource usage and limits.
+ # - #setquota: sets the resource limits for a given quota root.
+ # ==== +ACL+ [RFC4314[https://tools.ietf.org/html/rfc4314]]
+ # - #getacl: lists the authenticated user's access rights to a mailbox.
+ # - #setacl: sets the access rights for a user on a mailbox
+ # ==== +SORT+ [RFC5256[https://tools.ietf.org/html/rfc5256]]
+ # - #sort, #uid_sort: An alternate version of #search or #uid_search which
+ # sorts the results by specified keys.
+ # ==== +THREAD+ [RFC5256[https://tools.ietf.org/html/rfc5256]]
+ # - #thread, #uid_thread: An alternate version of #search or #uid_search,
+ # which arranges the results into ordered groups or threads according to a
+ # chosen algorithm.
+ # ==== +XLIST+ (non-standard, deprecated)
+ # - #xlist: replaced by +SPECIAL-USE+ attributes in #list responses.
+ #
+ # === Handling server responses
+ #
+ # - #greeting: The server's initial untagged response, which can indicate a
+ # pre-authenticated connection.
+ # - #responses: The untagged responses, as a hash. Keys are the untagged
+ # response type (e.g. "OK", "FETCH", "FLAGS") and response code (e.g.
+ # "ALERT", "UIDVALIDITY", "UIDNEXT", "TRYCREATE", etc). Values are arrays
+ # of UntaggedResponse or ResponseCode.
+ # - #add_response_handler: Add a block to be called inside the receiver thread
+ # with every server response.
+ # - #remove_response_handler: Remove a previously added response handler.
+ #
#
# == References
#--