If that is the case I suggest the following:
"Impro" by Keith Johnstone
"An Actor prepares" by Constantin Stanislavski
"Maximum Entertainment" by Ken Weber
"Magic and Meaning" by Eugene Burger and Robert Neale
"The Books of Wonder" (2 volumes) by Tommy Wonder
"Perform like a Pro" by Quentin Reynolds (This is a DVD)
"Greater Magic" by John Hilliard
Those are almost all focused on improving your performance and not tricks. The last one, Greater Magic is so that he can be truly overwhelmed by all the good magic out there and so he will focus on the "what will I do" as opposed to worrying about the how.
AB Stagecraft http://www.mindguy.com/store
Have you checked out Jack Dean's "Trilogy" yet?