If you are interested in the mastiff,  I highly recommend you learn as much as you can. There are many very good books on the market. These are the books I have hand picked as the best. Check out the Sandlot 2 movie , Buy it and see my mastiffs . Susie who is having pups soon,  is on the cover of the DVD and my dog Duke is the dog who played many of the brindle dog sceens . and Blackberry , Is from my kennel and was the brindle pup in many of the puppy shots,