Whether you want a quick quote or a long interview, an author can be the ideal person to contact. All non-fiction authors are experts in their own fields and so are many fiction writers who have done extensive research to give their stories authentic backgrounds. Even better, authors welcome extra publicity for their books so they are usually very co-operative with journalists.
What kind of interview?
From an author's point of view, phone interviews are the easiest as they don't take long and don't involve any travel. Radio interviews are more daunting and TV can be terrifying. It's worth checking your interviewee's experience beforehand so you can offer reassuring advice to those who have never done your type of interview before.
Fees and expenses
Many interviews are done for free, but some are not. To avoid wasting everyone's time, it's best to make clear early on whether or not you are offering a fee and/or travelling expenses.
Publishers will often pay author's travelling expenses to interviews, especially when one of their books has been published recently. But you or the author need to arrange this in advance. Assuming they will do so without checking can result in one of you being unexpectedly out of pocket.
If you are paying for travel, make sure you agree the mileage rate for car use in advance and make clear whether any rail ticket should be first or second class. Otherwise the bill may be larger than you expected.
Asking for help with research
Authors are usually generous with help to other researchers. They do research themselves and understand how difficult it can be. However, it's not fair to take advantage of their generosity and, if you do so, you risk souring the ground for the next person who asks. So, if you make extensive use of their information, make sure you mention them as your source. For TV documentaries and other major projects that are heavily based on their work, it's good to credit them as an advisor and pay a fee.