If you are thinking about being a dog owner, whether it's your first time or your first time considering a new breed, you'll want to check out The Dog Selector: How to Choose the Right Dog for You by David Alderton.
The Dog Selector provides an overview of 130 popular dog breeds with the goal of pairing a potential owner with the right type of dog for his or her lifestyle. Alderton provides a brief history of each breed as well as a "canine characteristics" chart which covers personality, exercise requirements, typical behavior at home and in public, grooming requirements, and common health issues. Of course, you'll see a picture of each dog and sometimes a puppy too!
Each chapter features ten breeds (which can vary widely in size and look) which share common characteristics that would make them good for beginners, or low-maintenance (and high-maintenance too, if you're brave and energetic), or good for people with allergies, or good for families, etc.