usually short
200-300 pages
when it's longer it's either because it's for academy (such as [[A History Of Western Philosophy - Russell - Bertrand]]) or because they feel like adding random anecdotes / opinion that does not add any knowledge ([[Chernow, Ron - The House of Morgan An American Banking Dynasty and the Rise of Modern Finance]])
cut the bullshit bro
storytelling probably (Taleb with Big Tony etc.)