This happens quite a lot in verbs e.g run to running. It is because you double the last consonant in a one-syllable noun for it to become a verb. (Keep in mind there are exceptions to this rule.)
The statement, which effectively uses a quotation to show Swift claim is this: SWIFT WRITES THAT 'THE POORER TENANTS WILL HAVE SOMETHING VALUABLE OF THEIR OWN' THAT CAN 'HELP TO PAY THEIR LANDLORD'S RENT.'
Quotation marks are used in write ups to indicate direct speech or texts; that is, quotation mark is used when an author wants to use the words of another person in his write up. When one is quoting a complete sentence, the first letter of the quoted word has to be capitalized, but when on is quoting a fragment, smaller letters will be used.
The adjective that is highlighted in the given sentence above is the word "all". This word is an example of an indefinite adjective. An indefinite word is used when it indicates a nonspecific amount or number of something or someone. The word "all" describes the word "books".
