diff --git a/tbku.txt b/tbku.txt
index cf5e111..5295316 100644
--- a/tbku.txt
+++ b/tbku.txt
@@ -86,15 +86,28 @@
   string of text that includes the machine name, system type, OS type,
   date, *and* the so-called *set name*.  The "set name" is nothing
   more than the suffix of the name of the fileset used to produce the
-  tarball, in this case, ``homedirs``.  Additionally, you'll also find
-  a log of the backup and "dot files" that tell you when the backup
-  began and when it ended. Here's part of what you might see if you
-  did an ``ls -al /bku``::
+  tarball, in this case, ``homedirs``.  
 
-    Mar 19 05:46 .mach.fake.org-FreeBSD-6.3-STABLE-i386-homedirs-begin
-    Mar 19 05:47 .mach.fake.org-FreeBSD-6.3-STABLE-i386-homedirs-end
-    Mar 19 05:46 mach.fake.org-FreeBSD-6.3-STABLE-i386-homedirs-20080319.tar.gz
-    Mar 19 05:46 mach.fake.org-FreeBSD-6.3-STABLE-i386-homedirs.log
+  Additionally, you'll also find a log of the backup and "dot files"
+  that tell you when the backup began and when it ended. Here's part
+  of what you might see if you did an ``ls -a /bku``::
+
+    .mach.fake.org-FreeBSD-6.3-STABLE-i386-homedirs-20080319-begin
+    .mach.fake.org-FreeBSD-6.3-STABLE-i386-homedirs-20080319-end
+    mach.fake.org-FreeBSD-6.3-STABLE-i386-homedirs-20080319.tar.gz
+    mach.fake.org-FreeBSD-6.3-STABLE-i386-homedirs-20080319.log
+
+  The "dot files" don't actually contain any information, but their
+  date/time stamps (you can see this with ``ls -al /bku``) will tell
+  you when the backup began and ended.
+
+  The log file contains a list of all the files that actually
+  made it into the tarball.  The log file also captures *the
+  errors* encountered during a backup.  This means that ``tbku``
+  is generally pretty quiet during a backup run.  It scribbles
+  any complaints it has into the log.  So... you should check
+  your logs regularly to make sure everything is working as
+  expected.
 
   You can create as many different filesets as you like (for as many
   different kinds of backups as you need).  So, for example, you may
@@ -185,12 +198,36 @@
   happens under one of several circumstances:
 
     1) You ran ``tbku`` without arguments, but there are no
-       "auto" file sets defined.
+       "auto" filesets defined.
 
-    2) You ran ``tbku`` with arguments, but no file sets with
+    2) You ran ``tbku`` with arguments, but no filesets with
        matching set names were found.
 
-    3) There are no file sets at all.
+    3) There are no filesets at all.
+
+  **Autodeletion Of Old Backups**
+
+  As shipped, ``tbku`` uniquely identifies each backup set based on
+  machine name, OS, CPU architecture, set name, and, most importantly,
+  date.  If you've set it up to run as a cron job, over time you'll
+  accumulate lots of older copies of backups.  That's because each new
+  day, the backup file name will change (since it include the date).
+
+  If you don't like this default behavior, change the ``TBKUDEL``
+  environment variable to be "YES". It must be *exactly* this string,
+  all in upper case.  Anything else will cause ``tbku`` to *not*
+  autodelete old backups.  This is intentional, to make it hard to
+  accidentally enable this feature.
+
+  Enabling this feature forces ``tbku`` to delete all older files
+  associated with the selected set name.  This includes the start/stop
+  "dot" files, the log, and the backup tarball itself.  In effect,
+  this option forces ``tbku`` to only keep the most recent backup of
+  each backup set.
+
+  *Use this option with caution!* If you only keep the most recent
+  copy of your backups in your backup directory, you may never be able
+  to get to changes made days, weeks, or months prior.
 
 
 **IMAGING WITH tbku**
@@ -233,14 +270,15 @@
   corresponding environment variable.
   
 
-  =================  ===============================  ======================
+  =================  ===============================  =========================
   **Env. Variable**  **Default Value**                **Meaning**
-  -----------------  -------------------------------  ----------------------
+  -----------------  -------------------------------  -------------------------
+  TBKUDEL            NO                               YES -> Delete old backups
   TBKUDIR            /bku                             Where to write backups
   TBKUNAME           $MACHINE-$OSTYPE-$OSREV-$HWTYPE  Tarball base name
   TBKUSETS           $HOME/tbku                       Filesets found here
   TBKUTAPE           /dev/sa0                         Tape device (or file)
-  =================  ===============================  ======================
+  =================  ===============================  =========================
 
 
   Examples::
@@ -253,12 +291,14 @@
 
     export TBKUTAPE-/tmp/faketape  # Tape backups actually written to *file*
 
+    export TBKUDEL="YES"           # Autodelete old backups when starting a set
+
 
 **OTHER**
 
   ``tbku`` was originally designed for use by experienced
   systems administrators and users.  As such, it does little
-  or no error checking.  If you define backup or file set
+  or no error checking.  If you define backup or fileset
   directories that are non-existent, for instance, you will
   get strange behavior.  ``tbku`` *will* try to create the
   backup directory you've specified if it does not already
@@ -317,4 +357,4 @@
 
     http://docutils.sourceforge.net/rst.html
 
-``$Id: tbku.txt,v 1.107 2008/03/19 20:02:36 tundra Exp $``
+``$Id: tbku.txt,v 1.108 2008/03/19 21:42:32 tundra Exp $``