The strength of this book is in its encyclopedic review of the literature on paragraphs and paragraphing. Scholars of the paragraph will appreciate the depth of research available in this book, and it will no doubt be of great use in future research on the topic. As to pedagogy, the text is an important reminder that although paragraphs might often be presented as simple and straightforward, they are in fact highly varied and responsive. McGee not only wants us to consider the context of the writer, the reader, and the text itself, but he demonstrates to us the necessity of this view. With these in mind, we can build our understanding of paragraphs as we read them, as we seek to write them, and as we teach others to do the same.
English for Specific Purposes

McGee has ultimately achieved his aim of writing a book that might ‘help writing instructors discuss paragraphs and paragraphing intelligently with their students’ by encouraging readers and writers alike to hold traditional models of the paragraph lightly, focusing less on the what and how of making paragraphing decisions and more on the why.

Iain McGee’s book about paragraphs is seminal.
If you have questions about how paragraphs function or how to treat them in your pedagogy, a handbook or Google might be your first recourse. But I would encourage that this book should be your first stop instead. McGee’s complex and descriptivist conclusions will not make the average composition instructor giddy with relief after having glimpsed something of the ultimate, but teaching writing is never a simple matter, and if you think paragraphs are a trivial side concern on the road to successful writing, McGee might dissuade you.
Understanding the Paragraph and Paragraphing, McGee offers a multidisciplinary path to the intense study of a central structural aspect of teaching writing. It is also an invitation to take up the quest again. Reading McGee’s book has inspired me to return to that path after a long absence.
Composition Studies Journal