Mystery book suggestions

[Jasujo]

I'm trying to figure out what to get my dad for Christmas. He likes mystery books, so I thought that might be a good idea. The only mysteries I've read are the ones my family has given me. I know he liked the Hannibal Lector books, but I've already given him those. He liked some Mary Higgins Clark, too. Does anyone have any suggestions?

Also, I might get my gram a mystery, too. She loves Alfred Hitchcock. She doesn't like swearing or "adult situations" in her books, though, so if you suggest something, please mention if you remember it having either of those. lol

Thank you very much!

[May]

I think Dean Koontz is a pretty good author. I think he's more in the horror genre, like Stephen King, but a lot of his books are somewhat mysterious too. There's not like a detective or anything though. Usually some fantasy/sci-fi involved as well.

[Byakuya San]

Agatha Christie has some classics which I'm sure everyone's read by now...but that's still no reason to give one of them (namely Murder on the Orient Express, Death on the Nile, and And Then There Were None) anyway!

[Bruces galore]

If she has not read them already your grandmother might like the Nero Wolfe books by Rex Stout. There are also cozy writers like Dorothy Cannell and Mary Daheim. I don't remember any bad language in either of those authors books. For your dad maybe Michael Connelly.

[Asthaloth]

If he's into Science (and I really do mean that) Some of Stephen Baxter's books could be classed as mystery.
Errr, off hand, the entire Manifold series (Space, Time, Origin, Phase Space) have a mystery element to them, but it's less "Whodunnit" as "Ultimate questions of human existence in the Universe" so I dunno?

Language may be an issue... The main character in those books (Same person different realities) is a bit of a "loveable rogue".
Actually, avoid Phase space, he gets quite... descriptive, about some Neanderthal rituals.