To convey the attitude expressed in this this collection of essays, one can hardly do so more forcefully than Russell in his own introductory remarks:
"I wish to propose for the reader's favourable consideration a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine in question is this: that it is undesirable to believe a proposition when there is no ground whatever for believing it true, I must, of course, admit that if such a belief became common it would completely transform our social life and political system; since both are at present faultless, this must weigh against it."
In this collection of essays Russell attempts to define and employ a moderate form scepticism that he believes to be compatible with a rational and scientific outlook. At root, he argues that we should acknowledge that even our best confirmed beliefs are likely to need revision, that we should not disregard expert opinion, and that, where there is no consensus of opinion among the experts, we (the non-experts) should suspend our judgment. Although the content of the essays in the collection varies considerably, this rationally sceptical outlook, together with Russell's well known commitment to freedom of belief and private action, provides a consistent thread througout.
Like some other collections of Russell's essays, this volume contains some that are quite dated ("Machines and Emotions", "Eastern and Western Ideals of Happiness", and "Philosophy in the Twentieth Century"). Nevertheless, the core is sound. In the handful of essays in which Russell explicitly outlines his sceptical approach to politics, religion, ethics and education ("On the Value of Scepticism", "The Harm the Good Men Do", "Free Thought and Official Propaganda", "Freedom in Society", and "Freedom Versus Authority in Education") we find timeless and compelling arguments for the application of the rational sceptical attitude.
Of this particular edition I have two criticisms. The first is a reasonably high rate of typographical errors. I have read several other Routledge Classics and I haven't noticed this to be a problem in the past. The second is a fairly unsympathetic introductory essay by John Gray, which seems to be more concerned with highlighting Russell's inconsistencies and criticising his rationalist programme than with introducing the subject matter of the volume.
But these are minor complaints. Overall this is a good, solid collection of essays by a great writer, noted philosopher, and perceptive social commentator.