Not terribly long ago, Cheryl S. Smith wrote a great book about dog parks, "Visiting the Dog Park," by Cheryl S. Smith, published by Dogwise. It's available everywhere books are sold, including at Amazon, Barnes and Noble, and Dogwise. It's the ultimate guide to using dog parks.
More recently, a sort of picture book for grown-ups was released. It's "fiction" but contains enough fact to be useful even to older children. "Dog Park Diary, the social round of Goody Beagle," as told to Kim Pearson, tells the story from the dog's perspective. Frankly, I wasn't sure of the message before I read it. But told from the dog's perspective and with wonderful photos by Anne Lindsay it points out the bully who is expelled from the dog park, the big dogs who get along with little ones, the little dog owner who is afraid to let her Toy dog play with large dogs, the greeting rituals among dogs, etc. For the dog fancier, the sight of Bichon Frise spelled as Bishon Frise thanks to an editorial oversight, might be a bit jarring but shouldn't put anyone off from the book itself. Published by Primary Sources Books, it's available online at Amazon and Barnes and Noble. A little pricey but probably at a better price point online, it would make a nice gift for the holidays.