There are a lot of great CI books, but few are as tactical as John Nolan’s seminal “Confidential: Business Secrets – Getting Theirs, Keeping Yours”. This is “the book” on elicitation. Unfortunately, it’s been out of print for many years. I paid nearly $100 to get a used copy some time back. Well it’s on sale *right now* at Amazon. Get one while they last.
If only there was a kindle version…