Surprisingly, Jovi wrote several songs (Just Older, Mystery Train, Say It Isn't So) with old friend Billy Falcon whose solo album "Pretty Blue World" Jon produced back around 91 or so (you know, the one with that song "Power Windows"). Other writing is mostly handled by Jovi-Sambora, except for a few weird names in there in She's a Mystery and Mark Hudson helped pen something too. Desmond Child only co wrote One Wild Night. Jovi wrote Save The World by himself.

Cheers,
jack