diff --git a/tools/chntpw.md b/tools/chntpw.md
index 9233447..a5f1635 100644
--- a/tools/chntpw.md
+++ b/tools/chntpw.md
@@ -7,6 +7,100 @@ This  manual page documents briefly the chntpw command. This manual page was wri
 chntpw is a utility to view some information and change user passwords in a Windows NT/2000 SAM userdatabase file, usually located at \WINDOWS\system32\config\SAM on the Windows file system. It is not necessary to
 know the old passwords to reset them. In addition it contains a simple registry editor (same size data writes) and hex-editor with which the information contained in a registry file can be browsed and modified.
 
+
+This little program will enable you to view some information and
+change user passwords, change user/group memberships
+in a Windows (NT/XP/Vista/win7/win8) etc SAM userdatabase file.
+You do not need to know the old passwords.
+However, you need to get at the registry files some way or another yourself.
+In addition it contains a simple registry editor with full write support,
+and hex-editor which enables you to
+fiddle around with bits&bytes in the file as you wish yourself.[1]
+
+```
+chntpw: Program for interactively resetting passwords and group
+memberships.
+My boot CD runs this with options -i -L SAM
+
+  chntpw: change password of a user in a Windows SAM file,
+  or invoke registry editor. Should handle both 32 and 64 bit windows and
+  all version from NT3.x to Win8
+  chntpw [OPTIONS] <samfile> [systemfile] [securityfile] [otherreghive] [...]
+   -h          This message
+   -u <user>   Username or RID (0x3e9 for example) to interactively edit
+   -l          list all users in SAM file and exit
+   -i          Interactive Menu system
+   -f          Interactively edit first admin user
+   -e          Registry editor. Now with full write support!
+   -d          Enter buffer debugger instead (hex editor), 
+   -v          Be a little more verbose (for debuging)
+   -L          For scripts, write names of changed files to /tmp/changed
+   -N          No allocation mode. Only same length overwrites possible (very safe mode)
+   -E          No expand mode, do not expand hive file (safe mode)
+
+
+
+ -u <user>   Username or RID (0x3e9 for example) to interactively edit
+
+Invoke the interactive edit menu on specified user.
+Specifying a user name will most likely fail if user has international
+character, so better to use user ID (RID), for example
+ chnptw -u 0x3e9 SAM
+to edit user with hexadecimal RID 3e9
+
+
+ -l          list all users in SAM file and exit
+
+Just that, list users in human readable form, with some info about if
+user is admin and if password is set.
+
+ -i          Interactive Menu system
+
+Invokes the menu system. Menu items will vary a bit depending on what
+registry hives are loaded.
+
+ -f          Interactively edit first admin user
+
+Select first admin user for edit. This is user with lowest RID that
+also is member of administators group, or built-in user 0x1f4 if not
+others possible.
+
+ -e          Registry editor. Now with full write support!
+
+Enter the registry editor. It is a small command system. ? for help
+there. See other documentation for more on regedits.
+
+ -d          Enter buffer debugger instead (hex editor), 
+
+Command line type hex editor, mostly for debugging purposes. ? for help.
+
+ -v          Be a little more verbose (for debuging)
+
+Lots of debug output during most operations (especially hive loading)
+
+ -L          For scripts, write names of changed files to /tmp/changed
+
+If any of the other functions changes the registry, the changed files
+are listed here. Can be used by wrapper scripts to know what to save.
+My boot CD uses it.
+
+ -N          No allocation mode. Only same length overwrites possible (very safe mode)
+
+Safe mode. Will only allow changes in registry that overwrites old
+values with same length data. Password reset only changes 2 bytes, and
+does not change value lenght, so password reset will still work in
+this safe mode. If something tries to violate this safe mode, a lot of
+error messages (some of the rather obscure) may occur.
+
+ -E          No expand mode, do not expand hive file (safe mode)
+
+Safe mode. Does not allow expanding the size of the file, but will
+allow adding keys/values as long as there is free space in the file
+already. (most files contains some free space)
+If expansion is needed but not allowed by this option,
+a lot of obscure error messages may occur, and file should not be saved.
+```
+
 Help Text
 -------
 ```
@@ -55,4 +149,4 @@ chntpw -u jabbathehutt SAM
 
 Links
 -------
-
+ 1. [pogostick.net](http://pogostick.net/~pnh/ntpasswd/)