This book is a quick but interesting read, presenting the alternative theory that the '82 Tylenol tampering took place somewhere in the distribution channels instead of the killer(s) going store to store. It's argued that one of the victims got their tainted Tylenol from a hospital dispensary rather than a retailer, and that there was a curious and targeted investigative fixation on a few lot numbers (essentially batch identifiers) of Extra Strength Tylenol.
There are a couple related books by the same author, one of them being TYMURS NYC about a young woman killed after ingesting cyanide laced Tylenol in 1986. This was after the triple sealed packaging for Tylenol was introduced in the wake of the '82 incident (foil bottle seal, heat shrink film over the cap, and glued box flaps). If I remember correctly, her boyfriend and immediate family weren't considered likely to have done the tampering, and another sealed bottle containing cyanide filled Tylenol capsules turned up at another store.
Just checked out the podcast, thanks for pointing it out. It's a pretty good overview, but spends a lot of time circling back to James Lewis as a suspect which Bartz believes is misguided. Not saying the Scott Bartz narrative is the last word on the matter, but he offers some intriguing theories outside of the standard Wikipedia retelling that I'd like to see explored further.