The core idea of the book is that you're not giving up smoking. You're just deciding not to smoke this cigarette. You can still smoke if you want to. You just don't want to because $HUGE_LIST_OF_BAD_STUFF.
I don't know if that's an evidence based approach, but some people find it useful.
My dad, who was smoking at least 40 a day (and really smoking -- down to the filter, deep inhalations, carried on when he knew it was doing him harm) read it and cut down for a week or so, but then started smoking cigars (in the same way as he smoked cigs), and then switched back to cigarettes.
I don't know if that's an evidence based approach, but some people find it useful.
My dad, who was smoking at least 40 a day (and really smoking -- down to the filter, deep inhalations, carried on when he knew it was doing him harm) read it and cut down for a week or so, but then started smoking cigars (in the same way as he smoked cigs), and then switched back to cigarettes.
I think the current evidence strongly recommended a combination of psychological work and nicotine replacement. https://cks.nice.org.uk/smoking-cessation