Is "With which" correct?

Question

I've been using "With which" many times but, days ago, an app corrected this structure. Then, what's grammatical or preferable?

With which book should I start?

or

which book should i read first?

Are other recommendable expressions? Thank you in advance.

Answer 1

It is correct. Pay little attention to automated grammar corrections.

With which book should I start?

Which book should I start with?

Both are correct, the former being the more formal of the two.