Here are some really cool books on how to raise and understand your Labrador Retriever, Golden Retriever, German Shepherd and Mastiff. You can get these at Barnes & Noble or Amazon for only $2.99, and you will learn a lot! These books will tell you lots of things about you dogs. You will learn some new tricks. Vince Stead has been raising dogs for over 25 years, and is the author of over 20 books.
The best selling book of his is one called "Sammy the Runaway Mastiff" about a big giant dog that breaks out of his kennel, and takes an adventure across the country meeting characters along the way. It's a fun book for children to read. The books about raising puppies and dogs, and lots of cool ways to make the behave better, is good reading.
If you like the military, Vince also wrote 2 books about it, called "Navy Fun" and "Navy Sea Stories" which are pretty good reads, like a travel book of different countries really, pretty fun to read.