Education Minister Adam Ingram MSP and author Debi Gliori will officially launch the scheme at North Berwick Community Centre.
Library officers and volunteers have been working flat out to pack prepared "Explorer backpacks" for 1,200 children who are due to start school later this year.
The packs are designed to boost children's skills and confidence as they prepare to begin primary school.
They hope to encourage a love of reading among young children, and also give advice to parents and carers on reading together at home.
Bookstart packs are already given out free to three-year-olds and primary one children.
The scheme is the first of its kind in the country.
Children will also be enrolled in the Backpackers Club and invited to try challenges and activities at their local libraries.