Difference between "kinds of books", "kinds of book", "kind of books" [duplicate]

Solution 1:

"Kinds of books" refers to multiple kinds and multiple books. "Kind of books" refers to a single kind of book of which there are multiple examples.

Solution 2:

In Garner's Modern English Usage (3rd ed.), Garner writes:

these kind of; these type of; these sort of. These are illogical forms that, in a bolder day, would have been termed illiteracies. Today they merely brand the speaker or writer as slovenly. ... Of course, it’s perfectly acceptable to write these kinds or these types or these sorts.

These is plural, so what follows must be plural; of books is not necessary for the phrase to make sense. Because a sentence such as "These sorts are up to no good" is perfectly grammatical (albeit a bit old-fashioned sounding), it's clear that both words should be singular or both should be plural.