This first part is jumping to a conclusion
「読むには読んだ」 means 'skimmed' a book. You quickly run through the book, but not intensively.
That might be the case, but it could also be the case that it was a very difficult book with difficult terminology, so it was difficult to understand. You cannot assume that person skimmed the book. Another example,
読むに読んだが、内容はほとんど覚えていない
. This could because they skimmed it, but it could also because they read the book many years ago and forgot the content (among other reasons). —
Jesse Good Jun 3, 2016 at 10:22