Back in 2004, Princeton University Press released a book entitled Garden Insects of North America, by Whitney Cranshaw. It was an incredibly comprehensive work. I just found out that an updated 2nd edition was released in 2018, and lists Whitney Cranshaw and David Shetlar as the authors.
How could it be improved on? It went from 656 pages to 704 pages. The claim is that there are over 33,00 full color photos, more than double the number of illustrations than the first edition. The authors have also expanded the treatment of native pollinators and the natural enemies of garden pests.
The first edition contained quite a bit of white space on pages throughout the book. This is gone in the current edition, I assume due to the better use of pages, and increasing the number of pages allowed for the huge increase in photos.
Realize that this is not a pocket guide for the field. It is a large and heavy book printed on glossy paper, allowing for better reproduction of the photos. The paperback currently sells for as little as $24.90 online. If you wanted one book to help identify garden insects, this is it.