I'm one of the few people who can claim to have purchased both Timothy Ferriss' Book and Penelope Trunk's book. Unfortunately Ms. Trunk's book I purchased at a dollar store. I did so because I wondered specifically why her book was there and Ferriss' book was a best seller. Here is someone who did everything right, but still her book is at the dollar store. So when I came across her delightful discussion of Ferriss, I was really pleased. Her book is not representative of her writing as a whole. It is dense, doesn't flow, and makes you feel excluded from the cool people before you even start. Ferriss' allure is that he claims his book is for everyone, which is complete nonsense (gramma isn't web savvy, and uncle Joe needs his dialysis). But he also generated an enormous upswell for his book from blogs like Trunk's.
Check out Trunk's blog for really useful tips from someone who looks like they should be the life of the party while hiding in the broom closet.