diff --git a/svkbd.1 b/svkbd.1
index 126c6c6..a41c68f 100644
--- a/svkbd.1
+++ b/svkbd.1
@@ -1,4 +1,4 @@
-.Dd May 29, 2020
+.Dd August 2, 2020
 .Dt SVKBD 1
 .Os
 .Sh NAME
@@ -6,31 +6,68 @@
 .Nd simple virtual keyboard
 .Sh SYNOPSIS
 .Nm
+.Op Fl D
 .Op Fl d
 .Op Fl g Ar geometry
+.Op Fl fn Ar font
+.Op Fl O
 .Op Fl h
+.Op Fl H Ar heightfactor
+.Op Fl l Ar layers
+.Op Fl s Ar layer
 .Op Fl v
 .Sh DESCRIPTION
 .Nm
-is a simple virtual keyboard, intended to be used in environments, where no
+is a simple virtual keyboard for X.org, intended to be used in environments, where no
 keyboard is available.
 .Pp
-The options are as follows:
+.Sh OPTIONS
 .Bl -tag -width Ds
+.It Fl D
+Debug mode; output verbosely to stderr.
 .It Fl d
 Set the _NET_WM_WINDOW_TYPE_DOCK property to hint windowmanagers it is
 dockable, by default off.
+.It Fl fn Ar font
+Defines the font or font set used. e.g. "Monospace:bold:size=20" (an Xft font).
 .It Fl g Ar geometry
 Adjust the initial window position or size as specified by the standard X11
 geometry format.
 .It Fl h
 Show the usage information.
+.It Fl H Ar heightfactor
+Affects the vertical space taken by the keyboard. One row of keys takes up
+1/heighfactor of the screen's total height.
+.It Fl l Ar layers
+Comma separated list of layers to enable (by name). If not set, all layers
+in the layout will be available. The layer names are defined by the layout
+you compiled.
+.It Fl s Ar layer
+The layer to show on program start-up (by name). If not set, the first
+layer of the layout will be shown.
+.It Fl O
+Disable overlay functionality.
 .It Fl v
 Show the version information.
 .El
+.Sh ENVIRONMENT
+The following environment variables can be defined, providing
+an alternative to some of the command line parameters. The command
+line parameters, however, always take precedence:
+.Bl -tag -width Ds
+.It \fB SVKBD_LAYERS
+Comma separated list of layers to enable (by name). The layer names are defined by the layout
+you compiled.
+.It \fB SVKBD_ENABLEOVERLAYS
+Set this to 0 if you want to disable overlay functionality.
+.It \fB SVKBD_HEIGHTFACTOR
+Affects the vertical space taken by the keyboard. One row of keys takes up
+1/heighfactor of the screen's total height.
+.El
 .Sh SEE ALSO
 .Xr XParseGeometry 3
 .Sh AUTHORS
 .An Christoph Lohmann Aq Mt 20h@r-36.net
-and
 .An Enno Boland Aq Mt gottox@s01.de
+.An Miles Alan Aq Mt m@milesalan.com
+.An Maarten van Gompel Aq Mt proycon@anaproy.nl