Quite possibly single-handedly responsible for reviving interest in philosophy among the general reading public (that is to say, the small proportion of the population that actually reads books), de Botton has certainly made philosophy accessible to me. I wanted to be interested in philosophy, but found the long-winded, overly abstracted and tortuous way it is generally written completely inaccessible. De Botton's engaging and laconic style, however, makes it available, and interesting, and applicable to the real world.
I started with The Art of Travel, which explores the experience of travel, why we do it, and which bits we focus on and which we ignore. Then I read The Consolations of Philosophy, which explores the approaches of various different philosophers to the common problems of life (love, death, meaning). Then I read The Architecture of Happiness, which looks at which types of architecture make us happy, and which make us miserable, and why. I am currently reading The Pleasures and Sorrows of Work. I've only got as far as chapter 1, on logistics, which explores why we ignore the romance of goods coming from far away places and being delivered to our doorsteps, and why we allow warehouses and distribution centres to be so ugly and boxy. But it's very good indeed and promises to be as interesting as his other stuff. I look forward to reading his next book, Religion for Atheists. A timely offering if ever there was one - there are plenty of religions which don't mind if you're an atheist (Unitarians, Quakers, Pagans and Buddhists all welcome atheists and don't try to change them into theists).
De Botton's writing does what good poetry and comedy should do: it looks at the world from a different perspective, and makes connections between things that no-one else had noticed a connection between. Presumably that is what good philosophy should do, too. He also asks why things are as they are, and whether the status quo could or should be changed - or, if he doesn't ask this question himself, he certainly provokes it in the reader, and gives the reader the conceptual tools to ask the question, and work towards an answer.
It is a truism that the in France, philosophers are held in popular esteem, whereas in England, they are regarded with suspicion. De Botton has single-handedly reversed that trend, so that it is cool to be seen reading one of his books. And about time too.
Of course there have always been people who enjoy Wittgenstein and Bertrand Russell and so on, but they were few and far between; now there are more people who read and enjoy philosophy, thanks to de Botton, who has succeeded in popularising something without dumbing it down.