I'm currently reading The Religion by Tim Willocks, a bloody historical thriller set during the Siege of Malta in 1565. It tells the story of Mattias Tannhauser, an arms dealer and former janissary who agrees to accompany a French Countess searching for her long-lost son on Malta.
Then the Ottomans arrive to wipe the Knights Hospitallers off the island and all hell breaks loose. Willocks doesn't muck about with his writing, the battle scenes are gory and brutal, and they give a vivid sense of the siege and the horrendous ordeal endured by the Knights and citizens of Malta. The story is pretty good too.
The only thing it doesn't have is a map showing the various bastions and citadels as they were blown to pieces, so I searched around online looking for a decent map for reference. I found maps of the time I could not see properly and modern maps with all the names changed so I gave up and carried on reading.
Then I remembered who I worked for, checked our backlist, found The Fortifications of Malta 1530-1945 with a perfect map on page 11 (it looks better in print). Guess where I'm looking first next time I open a book and need a map...