diff --git a/libisoburn/trunk/libisoburn/libisoburn.h b/libisoburn/trunk/libisoburn/libisoburn.h
index e1a05558..f918b44f 100644
--- a/libisoburn/trunk/libisoburn/libisoburn.h
+++ b/libisoburn/trunk/libisoburn/libisoburn.h
@@ -154,7 +154,7 @@ int isoburn_is_compatible(int major, int minor, int micro, int flag);
 
 
 /** Obtain the three release version numbers of the library. These are the
-    numbers encountered by the application when linking with lisbisoburn,
+    numbers encountered by the application when linking with libisoburn,
     i.e. possibly not before run time.
     Better do not base the fundamental compatibility decision of an application
     on these numbers. For a reliable check use isoburn_is_compatible().
@@ -296,8 +296,8 @@ int isoburn_ropt_get_input_charset(struct isoburn_read_opts *o,
            bit1= has_joliet
                  Joliet extension info is available (suitable for MS-Windows)
            bit2= has_iso1999
-                 ISO version 2 Enhanced Volume Descriptor is available
-                 >>> what is ISO 1999 good for ?
+                 ISO version 2 Enhanced Volume Descriptor is available.
+                 This is rather exotic.
            bit3= has_el_torito
                  El-Torito boot record is present
 */
@@ -350,7 +350,16 @@ int isoburn_igopt_get_level(struct isoburn_imgen_opts *o, int *level);
 
 
 /** Which extensions to support.
-    @param ext Bitfield: bit0= rockridge, bit1= joliet, bit2= iso1999
+    @param ext Bitfield:
+               bit0= rockridge
+                     Rock Ridge extensions add POSIX file attributes like
+                     owner, group, access permissions, long filenames.
+                     Very advisable if the designed audience has Unix style                          systems.
+               bit1= joliet
+                     Longer filenames for Windows systems.
+                     Weaker than RockRidge, but also usable with Linux.
+               bit2= iso1999
+                     This is rather exotic. Better do not surprise the readers.
 */
 #define isoburn_igopt_rockridge 1
 #define isoburn_igopt_joliet    2