Answer:
I am pronounced as one letter written with three. I come in blue black brown or grey. Reverse me and I read the same either way.
u always follow me but I am rarely seen
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I've told you all, I cannot tell you more. What am I?
What can you catch but never throw?
Men seize me from my home tear apart my flesh drink the sweet blood then cast my skin aside.
When is it bad luck to see a black cat?