I was fortunate to win a copy of the Safeguard Health & Safety Handbook. It explains legislation and references case law. I keep my copy on my desk as a reference. It helps me accurately and clearly advise directors and officers of their responsibilities. The book is collaborative effort by @Mike Cosman, @Ann Butler, @Craig Marriott, Michael Tooma and Rachael Schmidt-McCleave and I believe it is updated annually.
Like others I highly recommend Paper Safe & Challenging the Safety Quo. Another good one is 'Organising for Safety: How structure creates culture' by Andrew Hopkins. I'd also recommend listening to The Safety at Work podcasts by David Provan and Drew Rae. You can find them on LinkedIn (search for The Safety of Work or connect with David).