Steve VanSlyck wrote:
Pick up and examine any _professionally_ published book, magazine, or newspaper and you won't find double spaces,
OTOH, many _professional_ publishing systems _do_ use different spacing between periods and the beginning of a new sentence. The space is neither one nor two spaces, but intermediate. Some desktop publishing systems use an em space between sentences and an en space between words. IBM's Script/VS used two spaces on monospace font devices (like older printers).
Declaring this to be right or wrong based on your preference is hardly reasonable. You will find professionally produced documents with a variety of standards. Not all will satisfy the CMS reference you provided. In fact, my copy of the CMS (13th ed.) states that the spacing between words and sentences can be varied according to design and notes the standards for marking up text to increase or decrease spacing between words. Full justification of text requires variable spacing.
Mike