Reddit reviews What Doctors Don't Tell You: The Truth about the Dangers of Modern Medicine

A good place to start is to begin researching the AMA (and associated "health care" [sic] professions) as well as the various medical product companies -- especially from the perspective that the former are really "trade unions" designed to advance the agenda (including status and salary) of their own members over that of other people; while the latter are direct profit making enterprises (but also don't neglect that while non-profit organizations may be "not-for-DIRECT-profit" of the organization themselves, they most certainly can/are used as a vehicles for the "profit" of various individuals and companies that are associated with them).

I am not aware of a single (sole) source that I would consider to be objective or all-inclusive (even the various "history of medicine" books come from a limited perspective and ignore more than they cover).

You have to research it by reading across a lot of disciplines and topics. Alas, I do not have any specific book recommendations that would consider a good "primer" regarding the history (and around "modern medicine" in general, there are just so many, and a lot of them are out-of-print or hard to find -- though if pressed, I would tenuously suggest "What Doctors Don't Tell You" by Lynne McTaggart as a decent "starting" point because it begins with a bit of historical "perspective", and then follows that up with a lot of statistical-based-critiques of recent medical practices, and can serve as a launching point for your own further research).

My own has involved reading, over decades now (egads!), a rather vast array of books (and online materials) on a host of subjects, as well as reading encyclopedia entries (historical ones -- i.e. OLD books and encyclopedias -- are often quite enlightening, especially concerning things that were once widely known but which are no longer "politically correct" and as a result have dropped down the "memory hole" by subsequent edits and changing viewpoints & policies.)

Chief points to remember are that everyone has their own "perspectives" (biases and multiple underlying "assumptions") -- and just as a variety of conflicts and special interests and "mixed motives" are present in the current debate, so they also were present historically (although many of the "actors" and debate points were different).

In addition, people have a tendency to NOT be aware of the significant advances in our current mode of life versus what it was 50, 75, 100 years ago -- and that in taking for grantedmany "mundane" things which dramatically improved our overall health (whether abundant food, clean water, sewers, and central heating, not to mention "band-aids" etc) -- we often mis-attribute the roots of these many "innovations" and their affect on society (and the various special interests often distort their own history or involvement in past successes; and conversely ignore and/or whitewash their involvement in its failures and fiascoes).

IMO, one should take claims (especially those regarding stated motives and "noble goals" -- versus the unspoken ones) with heavy grains of salt, sifting through it all in an attempt to separate the wheat from the chaff, and arriving at your own opinion (which will obviously be "colored" by your own era and situation).

History is never as "clean" as it is portrayed in books. Like the present, it was a lot "messier" than we want to think.

To save some electrons: the PDFs linked above are photo copies of this book: https://www.amazon.com/What-Doctors-Dont-Tell-You/dp/0007176279
"What Doctors Don't Tell You" by Lynne McTaggart.

Here's a skeptical review of this book and it's associated magazine from Randi James: http://web.randi.org/swift/what-doctors-dont-tell-you-dangerous-advice

I have serious questions about whether the information in them is reliable.