Do you have a specific question that is related to DirectX? What is it that you need help with?

@Jason Z himself !!!!!!!! Ok I have Engine and I want to connect Physics engine with xna/c# (the same as DirectX) , I just need you to tell me if you can ! how to use BEUphysics or bulletX in my XNA game , it's complex and the documentation is weak??

I love your book

For sure it is possible, it is just a matter of how difficult it will be to add the two together.

Thanks for the comment on the book :)

I don't know how to integrate physics library into my game ?
Do I have to know the source code ?(it's complex)

i just need steps to do not more.

Most likely you will need access to the source code. Typically you will use a physics engine to determine the spatial properties of the objects in your scene, and then your rendering system would use that information to render the objects appropriately. I'm not familiar with the specific libraries that you mentioned, but in general you have to determine what types of objects you will be rendering (rigid bodies, plus skeletal bodies it sounds like) and then find out how to get that spatial data into your shaders in an appropriate way.