Brenda, is this the book you meant? http://youlookfab.com/welookfa.....-any-style
As to this list, 50-ish seems an eminently doable number for any given season to me, especially as we're again given a pass on innerwear, loungewear, activewear, sports gear etc, as well as shoes, scarves, bags, umbrellas and such. To those wondering what happened to the 'third piece' of the separates, I daresay adding 4 of those jackets to complete your 8 bottoms (skirts and pants) should do the trick? It really seems the only oversight, but climates do matter. I know my tropical summer & monsoon wardrobes call for more than 4 pairs of pants because the humidity kills with a single wear and don't even get me started on the grime... and I definitely need at least two raincoats/rain jackets/anoraks. But I think save for somewhat extreme climates (including mine), this basic list should be good for most.
I also found I thought of 'dressy coat' as something luxurious that would NOT come to office or playground with me, or even get worn on the airplane. Opera material, if you will? I just have to think of it in terms of a coat that would work with a silk brocade---be it a gown or a saree--and I can immediately see that it wouldn't ideally be a day-to-nighter, which is more a middle ground between workaday trench and this luxurious animal. Though I suppose depending on lifestyle one could just pick a silk trench as the day-to-night and cross one off the list! Warmth is the other factor though---to me, day-to-night suggests something warmer than a trench, in winter.
Similar thoughts on cocktail vs formal. I imagine the 'formal' dress as a longer, sit-down one, while the cocktail could take you dancing too, say.
Possibly what is most impressive to me is the non-specificity of this list, which the blogger notes too---a shirt to suit each bottom, as opposed to 1 white buttondown, 1 blue buttondown, 1 grey T-shirt, 1 black turtleneck etc. That's why it seems so likely to work for most people. It's accommodating of tastes and lifestyles. Good find, Suz!