DOB was a little concerned when he brought home the library stack last week and discovered a book about poison among them. (By the way, online catalogs and reserve systems at the library have to be one of the Greatest Inventions Ever.) I tried to reassure him that my interest was purely academic.
If you also have an academic interest in poison, say because you read a lot of classic mysteries, you probably would also enjoy The Elements of Murder, by John Emsley. I don't think it would be that helpful if you had a more . . . practical . . . interest in poison, and as the name implies it only deals with poisonous elements (e.g. lead, mercury, arsenic) as opposed to organic poisons.
But there's still lots of fascinating stuff in there, old murder trials, centuries-old mysteries, shocking past practices. (Did you know the ancient Romans actually used a lead compound as a sweetener? Makes white sugar look like a health food.)
And you never know, it might come in handy. One difficult poison case was diagnosed by a nurse who commented to the baffled doctors that the patient's symptoms were very like those in an Agatha Christie novel she was reading. So, more power to the academically morbid!