If you have time then writing a big substantial book can be a great way to capture and communicate your ideas. But the problem for most putative authors is that time is exactly what they lack. So an important decision for authors is whether they need to write a big book or if a little one will do.
Linear Effort
It is pretty much the case that a 600 page book is twice as much work as a 300 page book, and a 300 page book three times as much effort as a 100 page one. If time is an issue and a shorter book is suitable for your purpose then it makes sense to keep the book as short as reasonable.
What is “reasonable” in book length seems driven more by ill-considered conventions rather than any rational analysis. A lot of people seem to think a business book needs to be 200-300 pages; that’s why you read so many books that could have been written in 50 pages but have been pumped full of fluff. But given how important the length of the book is to whether or not you’ll actually get it done, it is worth challenging the conventions.
How Short Can a Book Be?
The first question is how the book will be received at a first-impressions level. If a book is only 30 pages long then people may not accept that it’s a book at all, they’ll say it’s a white paper. There is perhaps a lower boundary at around 50 pages for it to be considered a book with all the credibility that that implies. Now it may be that a brilliant concise 30 word paper will be more read, more discussed and more influential than a 400 page book—so we shouldn’t throw out the notion that maybe a white paper will serve our purposes as well as a book—but for now let’s assume we want something people will see as a ‘real book’.
If we accept that a book could be as short as 50 pages then the question becomes why would you write anything longer? It comes down to content. In a good 400 page book you wouldn’t want anything left out, you may even be wishing for more. I don’t think anyone ever wished Jaques Requisite Organization was only half as long. So of course, you write the book to be as long as it needs to be. But it’s a very different mindset to feel that the book will be as long as necessary, than to think you need to fill 300 pages with stuff.
Quality
Deciding that the book will be as short as possible can also lead to improved quality. With effort we often find the 1000 word essay can be made clearer and more forceful in 500 words. With the goal of writing a short book in mind we think “What are the really important ideas?” and “How can I express them crisply?”
So for most authors I suggest aiming to write a short book and if the demands of the content make it a longer one then that is fine. Just remember that a short high quality book will be easier for you write and better for you audience than a long one.
