It’s obvious to all but the delusional that there’s an inequality in the worldwide distribution of wealth. Some may defend it, some may mourn it, but it’s plain to see in any issue of National Geographic. John Kay’s heftily subtitled book Culture and Prosperity claims to show why these inequalities exist - a hopeful notion.

Kay tries to fulfill the book’s mission armed with a deep passion for economics and a missionary zeal to infect others with that passion. It should make for an approachable book. The problem is that Kay loves his subject a bit too much. He’s not just fond of mathematics; he’s a diehard fan. And like fans of any stripe — television shows, comics, sports, even books — he can’t seem to tell the difference between what will be of general interest and what will matter only to a select few. His knowledge of the subject also serves to blind him to the confusion of others, even while he clearly knows his understanding is above average. The result of these warring attitudes is a book that struggles to find its voice. One paragraph is written at level insulting to a high school economics textbook; the next may soar off into discussions of obscure theories known only to doctorates in science, with no middle ground. It’s an approach that will irritate readers of every level.

Kay does love his theories and tries to simplify them through examples. When he obtains examples from the real world, the approach sometimes works, although he has an odd talent for taking the immediacy from even the most topical subject. When he is driven to invent his own examples, the results are often laughable, as in an early discussion of worldwide “average incomes” using people with names so ethnic they may be trademarked, and with job/income ratios that only illustrate how far removed the study of economics is from its effects. Those examples which are successful deal with small phenomenon, rather than the large trends of the book, and lose some credibility from Kay’s own invented narratives.

Most disappointing is that, despite the epic subtitle, Culture and Prosperity never finds a unifying theme. One theory after another is discussed, in unmemorable detail, without the answers ever being tied together. Those stalwarts who plow through the entire book may remember the rules that govern supermarket checkout lines, or take away a better understanding of the Dutch tulip craze, but the initial question is lost moments after the intro, making only cameo appearances throughout the rest of the book.

It’s a shame that Culture and Prosperity is so scattered, because it addresses a subject worthy of focused attention. Nor is there any reason for economics to be boring. John Kay has found it interesting enough to occupy most of his life. Sadly, like many true fans, he can’t convey the essence of that which has so fascinated him.