Chantry Historian Achievement
Found all four chapters of "The History of the Chantry," by Brother Genitivi.
This is missable. Chapters 1, 2 and 4 can be found by visiting the Chantry during each Act. I recommend that you make visiting the Chantry your priority upon starting each Act so that you do not forget to do this.
Note: Chapter 3 is missable and is only available during the quest "Following the Qun" during Act II. After traveling to the Chantry at night, you will encounter a cut-scene where you discover Saemus' fate. Immediately after the cut-scene ends, use your targeting wheel by pressing to pause combat. The book will be on the podium overlooking the ground level of the Chantry. Select it with the targeting wheel to pick it up. You may also be able to grab it in between breaks in the combat if you missed it the first time, but it will be more difficult. If you are unable to pick it up before the cut-scene begins, simply reload your last autosave and try again.