How do you set a default theme to be used by emacs?

How do you set a default theme to be used by emacs?

[Daniel]

Hello,

I am having trouble finding out how to install a default theme.  I can
see a bunch of themes and select one and use it, but when I log out,
it's gone.  Here is my .emacs file:

(add-to-list 'load-path "~/
elisp")

(require 'color-
theme)

(eval-after-load "color-
theme"
 
'(progn
     (color-theme-
initialize)
     (color-theme-hober)))


I have tried to change the (color-theme-hober) to the theme that I
want, (color-theme-tty-dark)
But that doesn't work.
I also have tried to add (color-theme-tty-dark) after (require 'color-
theme)

I am not sure what I'm doing wrong. Thanks.