Acolyte's diary page is a page of Elei's Diary which can be found in the Temple of Aminishi in either normal or story mode. The Diary consists of 22 pages scattered throughout the first four rooms; Telekinetic Grab is required in order to obtain two of the pages. For the locations of all pages click on the map below.
One page in the third room (in the square-shaped room that sometimes holds a miniboss. The room has a passageway leading to it from all four walls, and artwork depicting a green and a blue dragon) is currently bugged so it does not appear in the NXT client all the time, but it does always appear in Java. However, it can be obtained using NXT by enabling area loot and trying to pick up something else nearby the spawn location. Alternatively, players can also go to the fourth room and back to the third room to make the page appear on the minimap and floor.
Once a page has been found, it can be inspected which will then add it to the book. If Elei's Diary is not in the player's inventory upon obtaining a page, that page is converted into Elei's Diary upon inspection, making it possible to own multiple diaries. Creating the diary for the first time prompts the message "This looks like the diary of a young acolyte. Seems like some of the pages are missing." Inspecting a page also always prompts the message "You add the page directly to the book. Judging by the gaps, you need [amount] more to finish the book."
Finding all pages completes The Book of Elei achievement which is both a master quest cape and Elite Dungeons achievement.