The Trials of Gilead
The first volume of the Trials of Gilead can be found in the entrance hall of the manor. It is on a table in the carpeted area facing the entrance door. This volume hints at the bow: Decorative Bow, which is found inside the Pool House. To reach it, Lara will first need the Grapple.
The second volume is found in the Library. This volume hints at the arrow: Decorative Arrow, which can be found inside the fire place in the main hall. To be able to reach the arrow, Lara first has to extinguish the fire by using a Bucket of Water.
The third volume can be found in Lara's Bedroom, right of the secret compartment holding the Journal. This book is sitting on a pedestal. This volume hints at the gear: Sculpture Gear which can be found atop the stack of crates in the main hall.