What does the phrase "slavering over the books restored" most likely…

Read the given passage and answer the four questions that follow:

I was completely charmed by Madhava Rao's antiquarian bookshop in Basavanagudi, Bengaluru. The stock was not chock-a- block with rarities, first or expensive editions. Its charm lay in stocking well-preserved old editions, some genuinely antiquarian, many out of print, all gathered fetchingly in one room full of gilt-edged spines, the smell of ageing leather creating an enchanting atmosphere. Rao's meticulous care and presentation made every copy desirable.

When I had finished slavering over the books restored, I insisted upon writing about his book shop. But Rao forbade it, relying solely on word of mouth to attract a select customer base. As I got ready to leave his bookshop, he suspected I might sneak a little piece of him after all. He made me promise that I would not write anything. But then 'When can I write about your bookshop?", I asked. He replied, 'When I finally close the bookshop.'

That moment came in March 2013, when he passed away from cancer at 78. Even on his final day, he completed book transactions before turning to his restoration work. A self-taught bibliophile and a perfectionist, Rao restored broken editions to exceptional condition, ensuring his customers held something truly valuable. Despite his passion, he kept a low profile, preferring solitude to study and restore his "antiquarian loot."

Before his death, he quietly sold his collection to a longstanding customer, ensuring the books were preserved. His legacy lives on in the hands of collectors who cherish his devotion to the art of antiquarian book-selling.