Canadian resources/ organizations which send books (fiction and non-fiction in good condition, no hardcovers) to prisons/ inmates in Canada.
You can find out more from the post on PEN Canada - Prisoners’ Right to Read
. There is also a mailing label you can print out to go along with any books you send. Note - books can not be sent directly to an inmate, but publishers, libraries and organizations (see above) can do so.
Of course you can't send any book, on any topic or anything which describes criminal activity. However, you can send books which will help inmates learn (or improve) their reading skills. You can also send non-fiction. Think about all those gardening, cooking, history and science books which you haven't looked at in years.