Merriam-Webster’s Dictionary of English Usage is a great book. It’s a hefty, well-researched, non-dogmatic guide to usage debates past and present, and I rely on it a lot.
But there’s a typo on the front cover.
A bit embarrassing to get the name of the book (and the publisher) wrong, so prominently. And it is wrong: on the dust jacket and the inside pages, the hyphen is there.
This reminds me of another book with a hyphen problem: Moby-Dick.
Yes, Herman Melville’s book is called Moby-Dick, with a hyphen. But the whale in the book is called Moby Dick, without one.
No one knows exactly why this happened. Melville changed the title (from The Whale) at a late stage in production, and perhaps a message got garbled or someone at the publisher’s put a typo on the title page of the first edition. Whatever the cause, the hyphen stuck.
My own theory is that the hyphen that should be on the cover of MWDEU fell through a freak wormhole in the fabric of spacetime and landed on the front of Moby-Dick.