Taran is a broadly trained computer scientist who contacted me a couple years ago and wrote a PDF for O'Reilly on another pet project of his, setting up a base in Second Life. He brought plenty of personal knowledge about languages to his reading of Masterminds of Programming. I think that, like me and many other people, he was overjoyed to see the famous creators of languages bearing their souls and airing their opinions about all manner of topics.
The book pulls together 28 contributors (I'm including in that count Sir Tony Hoare, who wrote the foreword), many of whom--such as Aho, Weinberger, and Kernighan; Jacobson, Rumbaugh, and Booch; James Gosling; Larry Wall; Bjarne Stroustrup; and Anders Hejlsberg--are household names in the programming community, while the rest ought to be. Some languages that you might consider obscure will no longer feel that way after you hear their place in computing history.
One example of a rescue from a near-death experience is Objective-C, which only began to pick up steam when Apple Computer released Cocoa for its desktop programming, and then with the release of the iPhone SDK has suddenly become the hot language of the year. Few of the thousands of programmers struggling with subtle Objective-C issues know of Tom Love and Brad Cox; this book will bring them into your living room. You'll find out, for instance, why Cox is leaving behind what he calls the "mud brick" level of programming and carrying on at a much higher level of abstraction.
But reading the interviews with Love and Cox won't instantly turn you into a better Objective-C coder. Masterminds of Programming isn't that kind of book. It's neither a reference nor a textbook, but a set of conversations. It's after you read a few of the interviews that you begin to feel the contours of your brain knocking on your skull to expand and let it stretch and twist about.
I might as well use this space to answer the questions I get all the time (including from my own managers, "Why wasn't (P or L) in the book?" where P is some well-known person, and L is the favorite language of the person asking the question. The answer: Federico and Shane worked enormously hard to contact every living language creator on a long list of languages. Tragically, a couple creators died during our contact phase. Others were too busy or had contractual barriers to participation. But the 28 who joined in make a historic collection.