"Have you written that book?"
Translation:Tu as écrit ce livre-là ?
French demonstrative adjectives make no distinction between "this" and "that"- ce, cet and cette can each mean either one.
Likewise, ces can mean "these" or "those". When you need to make this distinction (as in the given sentence) you can attach a suffix to the noun:
- -ci = "this" or "these"
- -là = "that" or "those"
Note, these suffixes apply to demonstrative pronouns, (celui, ceux, celle, celles), as well to remove ambiguity.
Usually, the addition of "-ci" or "-là" adds an intended nuance in meaning, since the French do not feel the need to differentiate "this" from "that" if it means they have to add a suffix.
In this sentence, and depending on the context, tone of voice, and body language, and when it is not comparative, "ce livre-là" can express surprise, despisal or admiration.