It's not uncommon to want to start a search as a result of something
read in a message so this is convenient.
(define-key map (kbd "C-p") 'notmuch-show-previous-line)
(define-key map "q" 'kill-this-buffer)
(define-key map "r" 'notmuch-show-reply)
+ (define-key map "s" 'notmuch-search)
(define-key map "v" 'notmuch-show-view-all-mime-parts)
(define-key map "w" 'notmuch-show-view-raw-message)
(define-key map "x" 'kill-this-buffer)