Hello every one !

I have posted a question already , but i think i did not formatted my problem exactly . So i am posting it again .

I am new  to Embedded system field . We all know that now a days Linux kernel is being used in most of the Embedded system .

I want a book or link , so that i can understand and can learn how and where we can make changes in the Linux kernel to make it compatible for a Embedded board (like any ARM board ).

I did not know anything about it , i want a fresh knowledge and start . So please help me from where i should start , i need your experience about some good book , and please tell me a good book which i should prefer .

Thank You!