Barbara Bush's literacy foundation raised over $110 million.
In 2013, Neil and Maria Bush founded the Barbara Bush Houston Literacy Foundation to carry on the former first lady's legacy as a champion of literacy.
The foundation's mission is to improve the quality of life for Houstonians of all ages through the power of reading, writing, clear communication and critical thinking.
The Barbara Bush Foundation helps increase awareness of the literacy crisis in America.
Before she passed, her foundation donated money to the Barbara Bush Library to replace books destroyed by Hurricane Harvey.
Mrs. Bush authored two children's books, C. Fred's Story and the best-selling Millie's Book, both of which have benefited literacy through proceeds from sales.
About 1,500 people are expected at the private service Saturday at St. Martin's Episcopal Church.
Barbara Bush Foundation highlights first lady's legacy as literacy advocate