This month, I received a newsletter that had an author's book entitled Get Client's Now! (The book's title is Get Clients Now! by C. J. Hayden. No apostrophe.) Check the source--that's an important proofreading tip. People don't like their names misspelled, and I'll bet authors don't like their book titles misspelled either.
Checking the source is worth the effort; and that's true for company names, addresses, phone numbers, dollar amounts, and numbers in a list.
Judy Beaver, The Office Pro
National Proofreading Day