This is actually my favorite book of all time. I even did a book report on Martin the Warrior when I was in the sixth grade.
Martin the Warrior tells the tale of Mossflower's most beloved hero. When we first meet Martin, his life is less than glamorous. He is a slave facing horrible treatment and conditions. However, it is not long before Martin fights his way to freedom only to later risk everything to save the Mossflower country that he loves so much.
What I love about this book, as with all of Brian Jacques's books, is the descriptive style that he uses. I can actually close my eyes and envision Martin in all of his warrior glory. Or see the feasts taking place in the Great Hall. I also feel that the characters are easy to relate to (eventhough they are animals). As the characters grow, I feel that the reader grows with them.
Once you have finished a Brian Jacques book, you truly feel as if you have been on a journey. And I enjoyed it every step of the way.