[Orgmode] trouble with Imenu integration

[Michael Gilbert]

And another....

Following the instructions from manual, I have this near the end of my startup 
file (I hope that is copied correctly):

        (add-hook ’org-mode-hook 
                   (lambda () (imenu-add-to-menubar "Imenu")))

But I get this error:

        Debugger entered--Lisp error: (void-variable ’org-mode-hook)
          (add-hook ’org-mode-hook (lambda nil (imenu-add-to-menubar "Imenu")))
          eval((add-hook ’org-mode-hook (lambda nil (imenu-add-to-menubar 
"Imenu"))))
          eval-last-sexp-1(nil)
          eval-last-sexp(nil)
          call-interactively(eval-last-sexp nil nil)


What am I missing?

— Michael