I could not stop noticing that some books have longer paragraphs than others. Patrick Rothfuss often use short ones in his books. Other writers such as Cornwell uses longer paragraphs before adding paragraph.
What is the technique behind this? Why a paragraph should be shorter or longer than others?
It's a stylistic choice. Some authors just naturally write longer, more complex paragraphs than others; how paragraphs are structured and divided is part of an author's "voice".
If you write sentences like Hemingway, chances are shorter paragraphs will also fit your voice. If you write long, complex sentences (like Mervyn Peake, for instance), longer paragraphs will also fit better. Sometimes, however, a single long sentence can form a complete paragraph (one paragraph = one complete thought); other times, a rather long set of short sentences can do the job for one reason or another.
