I found the book both interesting and depressing. In it, Warren comes across as someone whose first instinct was to "head for the political center" of an issue and use common humanity when he looks at it, rather than attempting to impose an ideological view on it. This resulted in him being almost unelectable (even in his day) as a politician (they tended to appeal to their base even in the 1940s) and unpopular as a judge (Eisenhower, who appointed him, left him swinging most of the time he was in office, and there were a number of attempts to impeach Warren).
I was surprised to learn, when I read the book, that California was considerably more right wing than it is today, with newspaper editors and owners combining with the heads of industries to treat workers poorly. It was that as much as anything that pushed Warren to "speak for the little man" whenever he could (his father worked on the railroads). Interestingly, Warren, who could just as easily have been a "Blue Dog Democrat" (to use today's parlance) but joined the Republicans to get the political support he needed to fill the term of a District Attorney who died in all.
The result of this book is that it might make liberals feel a little nostalgic about "days of yore" and infuriate conservatives who learn what rights he gave away. To my mind, that make this book a good read and I would recommend it to people who want to learn about previous periods of "judicial activism" and what caused them.