high 3, pushing the 4 and better than [b:The Book on the Bookshelf|95979|The Book on the Bookshelf|Henry Petroski|http://d202m5krfqbpi5.cloudfront.net/books/1320451642s/95979.jpg|1554589], but suffers from the same problem of apparently being a product of some writer-agent brainstorming session, "ah ha, let's produce a book about something intrinsic to reading/writing because at least some of the reading public will be interested in it." in this sense, similar to the New Yorker article on the topic of dice--seems to come out of a necessity to produce something, anything, rather than a deep-seated personal interest or love of the topic material.
Petroski, as a professional engineer, spends much time on manufacture, and missed the opportunity to provide chapters on pencil-sketching as an art form--or even the practice of court-room sketching where photographs are forbidden. Petroski's work is even and tempered, but he lacks the capability to "dance around" the topic as the best practitioners of non-fiction can--see [b:Krakatoa|25017|Krakatoa The Day the World Exploded|Simon Winchester|http://d202m5krfqbpi5.cloudfront.net/books/1348890801s/25017.jpg|2084098], nor does he elicit an imaginative universe of the time periods he describes.
high 3, pushing the 4; but Petroski's output was confined to the 80s and 90s probably due to lack of break-out bestseller status