The title of this post is one of the most common questions I get from people looking to write their first book. It’s usually code for, “I have to write how much?”. Most people either have no idea how long a book should be (which is perfectly understandable), or they have a slightly off-centre idea.

Judging a book by its thickness

The thickness of a book is not really a good indication of how much work has gone into it. A book’s thickness depends on a host of factors beyond the number of words. For instance, the paper used: the ‘bulky cream’ off-white paper often used by mainstream publishers is lighter but about 1.5 times thicker than pure-white (office) paper.

Then there is the ‘trim size’ (i.e. the height and width)...