This Movie was one of the best Audrey made - not an easy statement to make since she made so many great ones. "How to steal a million" is not as well known as her early works (Roman Holiday for example) or as well regarded as Breakfast at Tiffany's (Considered her Signature role), but it is far and away her best comedic work.The casting for the movie was very good. from the principals down to the supporting cast. Notice especially the casting of Hugh Griffith as Charles Bonnet in the role of Audrey's (Nicole's) errant but very endearing Papa, The interplay of those two Characters together with her scenes with Peter O'Toole as Simon Dermott (Society Burglar / Private Investigator / Love Interest) secured, to my mind at any rate, the movie's success. In addition, notice also the performances of Jacques Marin and Moustache as the museum security guards. Both of these turned in terrific work in supporting roles as did Charles Boyer in his (all too brief) appearance as the art Dealer DeSolnay. The sole weak point was I believe the casting of Eli Walach for the character of Davis Leland. Though his performance was adequate, he was not the best choice for this character (a role that was originally intended for George C. Scott). In Summary: The casting was wonderful, The characters were believable, Principals were excellent together and the dialog was bright,sophisticated and (did I mention?) FUNNY! Conclusion: This is one my favorite movies. I have watched it repeatedly over the years and it never fails to makes me laugh. So, If you like to laugh and especially if you're a fan of either Audrey or Peter then this movie is a "must-have". I rate it 10 out of 10.