Question

the author of these books speaking at the library this weekend.
is are ← action words
fill in the blank with the action word that matches the rest of the sentence.

Explanation:

The subject of the sentence is "the author", which is a singular noun phrase (the prepositional phrase "of these books" modifies "author" but does not change its singular number). Singular subjects require the singular verb form "is".

Answer:

is