Dear Mick LaSalle:“Oppenheimer” was a phenomenal movie with tremendous acting all around. I particularly liked Gary Oldman, in a brief role, as Harry Truman, and I wonder if his screen time was enough for him to be considered for the Best Supporting Actor Oscar? Is there a minimum amount of time in a movie needed to be considered for the award?

Joe Elson, San Francisco

Dear Joe Elson:There is no minimum. Beatrice Straight won a supporting actress Oscar for her five-minute role in “Network.” Still, there does seem to be a need for a brief or featured performance category.

As for Oldman, I liked him just fine, but I was thrown by the fact that he sounded nothing like Truman. I can hear Truman in my mind right now — he had a very distinct voice and accent, high-pitched and combative. I can do a pretty good Truman myself. I’m surprised Oldman didn’t attempt it.

Dear Mick LaSalle:When I saw “Prelude to a Kiss” on cable, I was mesmerized by Sydney Walker’s performance. The humanity, the warmth and complexity of his acting made me wonder why he wasn’t more well known.

Dave Sironen, San Francisco

Dear Dave Sironen: The humanity and warmth of Sydney’s acting was matched by his humanity and warmth as a person. He was not only the greatest man I ever knew, I believe that everyone who knew him considers him to be the greatest man they ever knew.

Sydney had a long career teaching and acting in the American Conservatory Theatre, and because my wife and a lot of our friends went to A.C.T., I got to know him. Watching him interact with people, I realized the enormous self-confidence it took to be as nice as he was, because he was constantly giving and, in that sense, risking rejection. I can only wish I were that brave.

His film career was taking off around the time he got cancer (he also played the bus driver in “Mrs. Doubtfire”), and I believe that if he’d lived just five more years, he might have won the supporting actor Academy Award. He was, as you’ve observed, a very great actor.

If there’s an afterlife, and if you want to know where you are, just ask at the gate if Sydney Walker is there. If he’s not, dress for hot weather.

Dear Mick:Besides “Fear the Night,” what otherMaggie Qmovies do you recommend that would support your contention that she is the female counterpart toLiam Neeson?

Dan Levitt, San Francisco

Dear Dan:She’s totally great in “The Protégé,“这是一个很好的展示what she brings to the screen.

Dear Mick:Bald is beautiful! Have you considered completely shaving your head?

Richard Kurylo, San Francisco

Dear Richard:Baldness builds character. Every man you meet that’s bald went through an agonizing process and came out the other side. I once considered writing a book called “Too Cool for Hair,” to help guys through the transition. But try as I might, I just don’t think bald is beautiful.

When I was a young man, everywhere I went, people told me I looked like Paul McCartney (and that was when McCartney looked like McCartney). Then somewhere around 30 I looked at my driver’s license photo and realized I looked a lot like Lee Harvey Oswald. Curiously, my current driver’s license photo, taken eight or nine years ago, bears a striking resemblance to Jack Ruby. I don’t know what this means, but it’s weird. Obviously, this has been trending in the wrong direction for decades. For that reason, I think it would be ungrateful to shave off the few hairs that have remained loyal, despite their loneliness up there.

Have a question? Ask Mick LaSalle at mlasalle@sfchronicle.com. Include your name and city for publication, and a phone number for verification. Letters may be edited for clarity and length.