This book is probably the best introduction to the Shakespeare authorship controversy available at the moment. What impressed me most about it was its tone of quiet logic, and its careful, balanced account of the facts and the arguments on both sides. The orthodox Stratfordians are given their due, and their arguments and their objections to the Oxfordian view are discussed in detail. I also liked the way that facts are put into context, rather than just baldly stated.
On the other hand there is a little repetition, and the chapters sometimes give the impression of being written as separate essays, and then tweaked a bit and put into book form. The first half of the book is devoted to the case against William of Stratford, and the second half to the case for Edward de Vere, the Earl of Oxford.
I'm certainly not a person who is inclined to accept conspiracy theories. As someone who has always loved Shakespeare and is interested in Elizabethan history, I dismissed the alternative authorship theory for many years as a crackpot idea. However, once I actually started reading the details of the arguments in favor of Edward de Vere (and reading other books on the subject besides this one), I soon became convinced. I think that a careful, objective consideration of the evidence shows that it is far more likely that de Vere wrote the plays than that William of Stratford did. The Stratfordian arguments seem labored and clumsy, and based largely on guesswork, while the Oxfordian view fits into place very easly and effortlessly, and has ample factual evidence to support it. For me this has added a whole new level of insight and understanding to the plays and poetry, and a much deeper appreciation and enjoyment of them.
Whalen's book is highly recommended for anyone who wants a good summary of the issues and arguments.