Writing press releases isn't rocket science, it's just a matter of following a few instructions in terms of layout and content. Getting your press releases out there can give your book a great boost and help your SEO and social proof. That's what you need when reporters come looking for an expert for an opinion.
You can cobble together a terrible press release, distribute it [free] online, and still get good backlinks to your site, improve your SEO (search engine optimization - which helps people find your site), and get better social proof (if reporters look you up, they should be able to find you).
If you write a great press release, though, you could get a call from a reporter, wanting to know more, asking you to send photos, requesting an interview.
Don't put it off, get a release out today. Your book deserves to be found and a press release can go a long way towards helping that.