What was the purpose of devotees giving books like 'Viveksindhu' to Baba, and what would he do with them?

As detailed in chapter 27, devotees developed a practice of bringing books to Sai Baba to have them blessed. When a desire to read a particular book arose, they would first give it into Baba's hands, hoping to receive it back as a blessing. It was believed that reading the book after it was blessed would lead to the acquisition of merit and supreme welfare. The text mentions Dasganu offering 'Santaleelamrut' and 'Bhaktaleelamrut', and another devotee offering 'Viveksindhu', which Baba then gave to Shama to keep in his records.