How did Calpurnia learn to read in To Kill a Mockingbird?

Calpurnia learned to read from
The Bible and a book 's grandfather gave
her. 

The Finch family
housekeeper Calpurnia is one of very few African-Americans in Maycomb who knows how to read. 
She was taught how when she grew up on Finchs Landing, Scouts familys land.  Her employer Miss
Buford taught her how to read using the Bible, and then she taught her son. 

Scout andhad no idea that so few African-Americans could read until they went to church
with Cal one day. 

Cant but about four folks in First
Purchase read€¦ Im one of €˜em.

Whered you go to school, Cal? asked
Jem.

Nowhere. Lets see now, who taught me my letters? It was Miss
Maudie

Atkinsons aunt, old Miss Buford (Ch. 12) 

Calpurnia, who is older that , tells Scout that she made her son
learn to read even though there was no school for him to go to because of his skin color.  She
taught him to read the same way that she learned to readfrom the Bible. 

No, I made him get a page of the Bible every day, and there was a
book Miss Buford taught me out ofbet you dont know where I got it, she said.

We didnt know.

Calpurnia said, Your Granddaddy Finch gave it to
me. (Ch. 12)

Calpurnias situation demonstrates the
inequality of racism and segregation.  There were no schools for African-Americans.  The church
was full of people who were illiterate, and they had to sing their hymns through a method
calling lining, where the person who could read would read the hymns and then everyone would
repeat them.  When Scout and Jem go to church with Calpurnia, they get a glimpse of the way the
other half lives in Maycomb.

The gift of the book for teaching reading
demonstrates that Atticus is not the only Finch who cares about others.  It seems to show that
Scout's grandfather had similar views of human nature, because he tried to help Calpurnia learn
to read.  She passed on what she learned to her son, creating two generations of educated
African-Americans.