The book The Pursuit of Happyness: …I had the resources not only to wear the kind of sharp suits I’d always loved but to…. My hope is that I can give the writer and editor of this book the resources to correct this common grammar error.

 Kind of is singular, but suits is plural, so therein lies the problem. With kind of, the noun following it needs to be singular (kind of suit); with kinds of, it needs to be plural (kinds of suits). When either kind or kinds is preceded by a demonstrative pronoun, it should be this or that for kind of and these or those for kinds of (for example, this kind of suit, these kinds of suits). Don’t mix them by saying these kind of suits or these kinds of suit. This should be discordant music to your ears.

The same is true for type/types of and sort/sorts of. The singulars—type of and sort of—should be preceded by the singular demonstrative pronouns this and that and followed by a singular noun, as in this type of book and this sort of problem, and the plurals—types of and sorts of—should be preceded by these and those and followed by a plural noun, as in these types of books and these sorts of problems.

In other words, everything should match.

Sherry