PP Quimby was a seminal American mystic and healer who was more or less the father of the New Thought movement, an ecumenical movement in 19th and 20th century Christianity that promoted(s) the idea of an omnipresent and universally accesable deity. The key characteristic of this teaching is that you and I have access to real and practical spirituality at every moment and that we can move closer to healing and well being through the use of our own mind and imagination.
Mary Baker Eddy was one of Quimby's patients and the founder of Christian Science, a Christian denomination that is very centered around spiritual healing.
If you peruse the other reviews of this text you will note a controversy with two sides holding forth. The controversy stems from the following: Quimby put forth religious ideas that were open to all, didn't need a church, and were radically personal and anti-denominational. Mary Baker Eddy created a church after studying with him which embraced an orthodoxy using very similar ideas to those which Quimby used. Quimby's later admirers accused her of appropriating his ideas to create a legalistic, theocratic institution which lost the liberating spirit of what he taught.
This text, for Quimby followers, is evidence of her misuse of his work. They site it as proof that she drew her theology from his teaching and used it to further her own ends. For Eddy followers, "The Quimby Manuscripts" does not function as proof and some even go so far as to say the text is an elaborate literary contrivance created to vindicate the folks who had a bone to pick with her. It is true that the author (Horatio Dresser) was in contention with Eddy and her followers but it is also true that Eddy almost certainly gained much of her insight from Quimby's visionary nature if not from the letter of his words. After all, he was both her Physician and her mentor.
Having written all of this, I will offer my own opinion in three parts:
A) Horatio Dresser knew Quimby's ideas as well as or better than anybody and the ideas are good and truthful. This book is an excellent resource for anybody interested in some of the root concepts behind what has become New Thought metaphysics. I believe that Dresser was a good, sincere and highly intelligent man and that he communicated important ideas to the world.
B) If you are a true student of healing and truth, whatever your particular path, it is worthless and destructive to engage in sectarian bickering. If there is one God that loves everybody, as taught by both Quimby and Mary Baker Eddy, than to quibble over interpretation, theology or authorship is an exercise in time wasting which could be better spent in personal practice of study, prayer, meditation, service or just day to day living.
C) I personally don't care for Churches or religious systems but I have met wonderful people from Christian Science. I say, if it works to make a person better, more power to them. But whether you like to go to a Church of some kind or prefer not to, why waste energy yammering about which system or teacher is "Right?" Isn't that what Jesus (not to mention countless other masters from other belief systems) warned against over and over again?