Caapi has a long history as the master plant teacher. A current new good book is "The Year of Drinking Magic, Twelve Ceremonies with the Vine of Souls" by Guy Crittenden, excellent reading.
Have also noticed googling "pure caapi extract", modern extracts are standardized in purity & ratio of alkaloids with over 50 reviews. They have come a long way in the past few years, as for decades they were un-standardized, questionable purity, and based on unrecognizable ratios of 30:1, 15:1, 20:1, which causes a lot of confusion and endless questions.