A History of Philosophy in the Twentieth Century, by Christian Delacampagne.
This is the book I was looking for, that treats both of the major traditions in Western Philosophy, the "Continental" and the "Analytic" or "Anglo-American" equally, and to a background of the major historical events of the last century. The author is French, and was brought up in that tradition, but he seems to have a considerable understanding of the Analytic schools; just how profound that knowledge really is is impossible to guage from the small 'bites' necessarily devoted to each major philosopher. His rather glib assertion of Wittgenstein as "the most important philosopher of the twentieth century" is not really backed up by any imposing evidence as to why (just because others say so?) but his summary of that thinker is as enlightening as any other that I have read. He covers Frege and Husserl thoroughly (and their common ancestor Bretano). The many aspects of Bertand Russell are given their due place also.
While he tries to be as unbiased as possible, he is clearly coming from a somewhat leftist perspective politically. He treats Marxism and its many offshoots as almost a third tradition - justifiably perhaps, considering the huge influence of that philosophy over half of Europe during this period. One might however object that Marxism is more than a philosophy, incorporates many other disciplines, and is perhaps closer to a religion, and religious thought of any other sort gets very scant attention in this book.
Several times he feels compelled to state that Stalinism cannot quantitatively be equated with Naziism, and despite his arguments I still
feel compelled to disagree with him on this, as well as several other assertions.
Naturally enough he is also not one of those who would choose to separate Heidegger's philosophy for his political sympathies, and he comes down very heavily on the Sage of Freiburg numerous times. Nevertheless he is, somewhat amusedly, constantly compelled to acknowledge the latter's great influence on numerous succeeding thinkers, and having to spend many paragraphs in trying his extricate the pernicious effect from these followers, in order to excuse them from their assumed creditor's faults.
If anything Delacampagne would seem to place himself most in sympathy with the conceptual historicism of someone like Foucault, or the neo-Marxism of Louis Althusser, to whom he devotes, in my opinion, an unjustifiable amount of space. But he does give pretty well everyone a fair shake of the dice in general, from the Positivists, Popper and Carnap, to the Ordinary Language School, Ryle and Austen, right up to modern relativists like Derrida and Rorty. His last figures are, appropriately, mainly American; figures like Rawls, Putnam and Cavell are given space, none of fitting comfortably into either major European tradition.

All in all, an impressive and stimulating read for someone who really wants to get to know the basics, from which he (or she) can proceed further with areas of interest.