Few books at the intersection of business and self-help are worth purchasing or reading. However, Pitch Anything is worth both the time and money, particulary for people doing business in the US.
Although Klaff does not cite many sources, his "hot cognition" ties in with some of the work of Daniel Kahneman and Malcolm Gladwell. The crux of Klaff's approach is to pitch the part of the psyche which actually makes decisions - the "gut" or subconscious. Keeping pitches well away from the boredom threshold is critical. Establishing the authority to pitch through the use of "frames" is a key insight. Klaff also outlines how to leave prospects chasing you to sign up using the best of advertising psychology from Madison Avenue.
Perhaps most entertaining and instructive are Klaff's anecdotes about his own pitching experiences, illustrating the methods he outlines.
One of the few caveats with this work is that Klaff's approach likely requires some adjustments for business cultures outside the US. However, the principles are fundamentally human and can be translated across continents and generations.