e.e. cummings
Aw, he had something in common with his ex, Robyn Rihanna Fenty.
Kristen Bell is a somewhat example. Her full name is Kristen Anne Bell and when she was very young, she decided she didn’t like the name Kristen. So her family dropped her first name and she was known as Annie Bell by everyone through her years in school. It was only when she was an adult and starting as a professional actress that she decided to go back to her original first name.
Eldrick “Tiger” Woods
Minor nitpick: I’ve been reliably informed, by this very board, that it is E E Cummings (which is how the author signed himself). The lowercase version being a book jacket logo.
There should be a spot here for Prince Rogers Nelson.
Sure, originally he dropped everything *but *his first name, but for a while we had the “artist formerly known as Prince” days, when he dropped that as well…
I think I’ve shown that I can. 
I note that at least 50% of the respondents didn’t read/grasp the OP’s very clear statement about not wanting people who used two initials instead of their full name.
Jackson DeForest Kelley
The SDMB comes through! Although I’ve compiled a longish list already, a good three-quarters of these are new and perfect additions.
Keep it up. General credit will be issued if I complete the project.
That’s okay, I’d rather have to pick through for good entries than miss any, and two-initial folks who aren’t 1900-1970 Brits qualify.
I think the most fascinating thread in the whole topic is that there are no fewer than six US Presidents who served under names different from their birth certificates… and that’s not even counting Harry Truman or any spurious claims about the current guy. Quick, name the Prez who completely changed his birth name…
Gerald Ford–Leslie Lynch King, Jr.
T. Boone Pickens
and O. J. Simpson, of course!
And a couple of Watergate superstars: E. Howard Hunt and G. Gordon Liddy
Polly Jean Harvey usually goes by PJ Harvey.
That’s such a hoot.
…and how I could not have that on the list already is as mysterious as the Affair of the Glove…
P.J. O’Rourke
P.J. Soles
Ozzy Osbourne
Geezer Butler
Lemmy Kilmister
M. Emmet Walsh
Clyde Turk Pipkin
When did he change his name? Being “the Lynch King” during the Civil Rights era would be … interesting.
Bonus: Bill Clinton was born William Jefferson Blythe. He took his stepfather’s surname later.
I didn’t realize that Gellett Burgess had dropped his first name altogether – no first initial, even. His real name was Frank Gellett Burgess.
If you’re wondering who he was, he’s the guy who wrote “The Purple Cow” and its sequel
I never saw a Purple Cow
I never hope to see one
But I can tell you anyhow
I’d rather see than be one
He also invented the word “blurb” and was the first to use “Bromide” in the sense of “an overused adage”. It was his MIT training coming through.
I was also surprised to see that, for a long time, Penguin Books was selling the works of George Bernard Shaw as by “Bernard Shaw” (Long before the cable news host was around). I don’t know if Shaw himself used his name that way, but I usually see it with the “George” in front. Again, no indication by way of an initial that there was ca “George” in front there.