Which is correct to write in one line, or are more than one correct
(you can copy and use "x" if you want):

[ ] Chapter II. A New King Was Born
[ ] Chapter II - A New King Was Born
[ ] Chapter II: A New King Was Born

Thanks!

What are you outlining?  A book?
If there is a rule, it may be specific to the context.

fwiw, I like the dash.  "Chapter II" and "A new king is born" are
different titles for the same pages.  The reader's pause after reading
the period is too long, and I take a colon to mean "a list follows."

But the one you choose may just be a matter of personal preference.  Best wishes.

A colon is actually a full stop in a sentence, what comes before the
colon should be a full sentence, but what is after it doesn't need to
be. Essentially what comes after the colon is just a continuation of
the thought before the colon, or it illustrates what you said before
the colon.

How to effectively use a colon is explained well here:

http://www.ryerson.ca/writing-centre/punctuation.pdf

That aside, editing punctuation for a book doesn't always follow
proper english language punctuation. Personally I like the dash as
well.

forge

The dash is acceptable, but I vote for the colon as the best choice.
That's just my personal viewpoint.

The only one of these three options that looks "wrong" to me is the
first, which uses a period (full stop).

I've been thinking about this matter, and it seems to me that this is
a variant of title:subtitle, as in "Star Trek: The Next Generation."
Most manuals of style suggest using a colon in such cases.

"According to the 15th edition of The Chicago Manual of Style
(University of Chicago Press), 'a colon introduces an element or a
series of elements illustrating or amplifying what has preceded the
colon.' But it also advises that when referring to a book, in text and
in bibliographies, a colon should be placed between a title and a
subtitle, regardless of how they appear on the title page."

The Chronicle of Higher Education
http://chronicle.com/free/v50/i18/18a01401.htm

Hrmm. Thanks Pinkfreud, but if you're right, than I made the wrong
choice finally here:
http://www.authorama.com/true-version-of-the-philippine-revolution-3.html
(I used colons). I would actually like to know the most correct way of
doing this for Authorama, but with these comments I suppose either
it's not a clear issue, or just depends on taste...

Thanks Daytrader -- yes, this is for a book, see link above.

Forge -- I take it a colon then might be wrong, as I don't want a full stop?

Hello JP,

In most cases, I would agree on the use of the colon but it's a bit of
a 'house style' issue and your own sense of aesthetics.   Style guides
are sometimes just la-de-da suggestions, while grammar and punctuation
'rules' have more of a "you veilll comply (Laurence Olivier waiting in
the wings with dental tools)" edge.

Most academic writing and source manuals will trend toward colon
usage, but I took a look at your URL and the periods after your
chapter numbers look quite snazzy to me.  As long as you don't have
someone nagging to do it 'their' way, I would satisfy myself
artistically.  On the particular page you reference, with the bullets
in between, a colon might tend to over-dot the eye of your reader at
mid-level and the en dash, IMO, would be too disruptive.

Also not to muddy the waters, but generally Roman numerals are
reserved for parts of a book (preface, acknowledgments); Arabic for
chapter numbers.  I do, however, think the Roman numerals fit quite
nicely with your subject matter.

In the U.S., there's a general trend away from Roman numerals
altogether.  We see that quite a bit in medicine.  We follow the style
guidelines of the governing agencies (AMA, APA, JCAHO, AHA) and
sometimes they blow like the wind.  Recently there was a change by the
ADA from type II diabetes mellitus to type 2, so style guidelines or
the way something is written is rarely cast in stone.

I've also seen chapter numbers spelled out (Chapter One) which seems
kind of flowery but it's another way to go.  I'd choose a style based
on eye appeal and content and just be consistent throughout.

Since yours is an eBook, I would opt for the utmost in unobtrusive
punctuation.  For me, in this particular case, that's a period.  It's
not the most 'correct' way but it's 'stylish' and completely
acceptable.  However, if your chapters were aligned one underneath the
next, my vote would go in the colon column.

Your mileage may vary.

The Waffle Cone of * V *

Speaking professionally, if I were your editor, I would use the period.

Archae0pteryx

It appears that the consensus is that there's no consensus. In such a
case, I think the best thing to do is to follow one's own taste. Or
write a book with no chapter titles. ;-)

Voila, thanks. As for Roman vs Arabic numerals, for that I follow the
style of the Gutenberg text I use as basis for my HTML conversion.