My own A Scream of Consciousness and Refuse to be Afraid run about 90 pages, in part because, well, I said all I needed to say in that space.
In his introduction to his translation of Abandonment to Divine Providence, a k a The Sacrament of the Present Moment, John Beevers writes:
Short books often have great power. A few that come to mind are Thomas à Kempis' The Imitation of Christ, the Communist Manifesto, Paine's The Rights of Man, Rousseau's Social Contract, St. Thérèse's The Story of a Soul and, of course, the Gospels. There is a very human reason for this. Most people have neither the time nor the inclination to plough through a five-volume treatise. They want the message, whatever it is, given to them in as few pages as possible. This is no new phenomenon. Pamphlets may not give as much enjoyment as a many-volumed book, but it is arguable that they have had vastly more influence.I would heartily recommend the Domino Project books – Godin's We Are All Weird or Poke the Box, Read This Before Our Next Meeting by Al Pittampalli, Anything You Want by Derek Sivers, or Do the Work by Steven Pressfield, for example – or of course my own humble efforts (see the right sidebar for previews).
And it is not only the reader who is affected by a short book. Its writer is. The effort, whether conscious or not, to concentrate his thought into a hundred or so pages instead of a thousand, gives this thought a sharpness and urgency which would inevitably be diffused over many volumes.
I'm not going to suggest that these are as good as those books Beevers rattled off, but they do pack a punch, if I say so myself.
The Sacrament of the Present Moment, of course, plays an integral role in the ideas in A Scream of Consciousness. From the pages in the Amazon preview I think Beevers' translation might be a little more accessible than the one I read by Kitty Muggeridge, but it's the ideas of Father Jean-Pierre de Caussade that resonate in any case.