Assuming "学校で読んでいる本は簡単なの?" translates as "Are you finding reading books at school easy?", is there a general nominalising rule here?
From another question about こと and の, it's clear that the generalised act of reading would be 読んでいるの. Since 読む can take a direct object with を, it would follow that adding a noun that can be read like 本 or 新聞 allows you to be more specific.
How far can this be taken? For example, if I like reading books and newspapers, could I say "読んでいる本と新聞はすき"?
Is this correct and how is the rule actually formulated?