I've read a _lot_ of (and about) Jaspers, but this book has proven the most effective resource for my Jaspers studies.
Ehrlich, Ehrlich, and Pepper selected excerpts from throughout Jaspers' career in philosophy (not a lot from his psychology, as the title indicates). They then grouped these texts together in logical and cohesive sections, adding short introductions to each section as well as each individual text. The result: it is possible to sit down and read the collection cover-to-cover and feel the continuity of the work.
E, E, and P have gotten over a major hurdle in making Jaspers' work accessible. Many of the available translations of Jaspers are sub-par. Jaspers' frequent coinage and usage of technical jargon has posed a translation problem (i.e. words that no one knows exactly how to translate) that has resulted in discrepancies between translations. E, E, and P resolve this (to a large degree) by retranslating or correcting many of the passages in this book. Since I happened to have both a German and an English (trans. E. B. Ashton) copy of Jaspers' 3 volume work "Philosophie" -- a text quoted often in this volume -- I compared translations. E, E, and P's revisions to E. B. Ashton's translation were consistently more readible.
In addition to providing a fantastic overview of Jaspers, this volume does have a couple of other highlights:
* Many passages translated from Von Der Wahrheit -- Jaspers' last major work (which remains largely untranslated).
* Great coverage of some of his writings on religion (Buddhism, Christian mysticism, etc.)
* Selected entries from his journals.
* Correspondence with other philosophers (notably Arendt and Heidegger).
In short, I highly recommend this book for those looking for a good Jaspers reader. If you are new to Jaspers, I would also suggest reading Philosophy of Existenz -- a great (and short) overview of Jaspers' project.