There are two common misconceptions about supply-side that still pervade common thought. The first is confusion between supply-side theory and what was packaged as supply-side economics during the 1980 U.S. Presidential campaign. The latter was merely a limited set of policy positions, mainly dealing with tax issues, designed to combat the prevailing condition of the day known as stagflation. The prevailing Keynesian theory did not even consider such a condition possible and hence provided no solution to the problem. Hence the harsh and caustic rhetoric that was used to finally displace the Keynesian "Tax and Spend" policies of the day. [Keynes never intended for deficit spending to go on forever and in his defense, F.A. Hayek (Austrian school) wrote later that had Keynes lived longer he would have been a determined figher against the inflationary policies pursued in his name.] While these politically packaged policies did follow supply side theory, they were not representative of a total economic model and therefore were criticized on that basis.
The second issue is the even more ridiculous notion that supply-side theory has been disproven or violates all other economic thought. This could not be further from the truth as Canadian economist, the father of supply-side economics, Robert Mundell won the 1999 Nobel Price for his theoretical work (Art Laffer compliled most of the emperical evidence). In fact, after 35 years of consumption based (demand side) Keynesian theory, supply-side was a reaffirmation of [Jean Babtiste] Say's Law: Commodities are ultimately paid for with other commodities. Say stated that "The encouragement of mere consumption is no benefit to commerce; for the difficulty lies in supplying the means, not in stimulating the desire of consumption...Thus, it is the aim of good government to stimulate production, of bad government to encourage consumption" (1834). All economic schools embrace Say's law including Classical, Monetarist, Austrian and Supply-Side, except Keynesian. Even President Clinton's 1994 economic report stated "It is undeniable that the sharp reduction in taxes in the early 1980s was a strong impetus to economic growth". Unfortunately 40 years worth of economists forced homage only to Lord John Maynard Keynes are having a hard time adjusting to the failure of demand side theory.
This book scares the Keynesian establishment, and it should--they are gradually going the way of the Newtonians. The only criticism of Wanniski (and of supply-side in general) seems to be ad hominem--some of which may be read in other reviews here (the nonsense written by Donald about Hoover and the Depression demonstrates a complete misunderstanding of the book's major theme).
Even irretrievable leftists, though, can find much in this book over which to ruminate. Wanniski is notably non-partisan and seems willing to share his ideas with whomever will listen. I found his group's web site after reading his book, and he posts a daily letter which is usually just as absorbing. If you have doubts about ordering the book, go to the site and read a few of his memos.
Over time, I think that _The Way the World Works_ will join _The Wealth of Nations_, _Das Kaptial_, and _The General Theory of Employment, Interest, and Money_ as one of the great treatises on economics--and it is by far the most fun to read.