Books About Letterboxing

The Letterboxer's Companion by Randy Hall (Mapsurfer) now in its 2nd Edition
It's a Treasure Hunt! Geocaching & Letterboxing by G & R Publishing
Dartmoor Letterboxes by Anne Swinscow
More Dartmoor Letterboxes by Anne Swinscow
101 Dartmoor Letterboxes: But Not How to Find Them! by John Hayward and Anne Swinscow
Dartmoor Burial: A Claire Camden Mystery by Audrey Peterson (letterboxing elements in story)
Chesapeake Crimes III (anthology) (short story about letterboxing "Inked to Death") Shelley Shearer (Knights of Columbo)
Scavenger by David Morrell (letterboxing elements in story)
Let's Go Letterboxing by Janet Palmer (out of print)
Dartmoor Letterboxing by Kevin Weall (out of print)

Books Authored by Letterboxers

The Letterboxer's Companion by Randy Hall (Mapsurfer)
Clues to Food: A Letterboxing Cook Book by AM Jenner (Romana and Heart Writer, with recipes by dozen of letterboxers!)
The One King by Angela Ballou (Wyvern)
Chesapeake Crimes III (anthology) (short story about letterboxing "Inked to Death") by Shelley Shearer (Knights of Columbo)
Yesterday, I Will (anthology) featuring short stories by Chrissy Lewin (Brandy), Mischa Borgnaes (Romana), and Becky Rohner (Heart Writer)
Tanella's Flight by Anne Marie Jenner (Romana and Heart Writer)
Road Song by Natalie Kusz (Fat Lady)
A Heart Full of Diamonds by Anne Marie Jenner (Romana and Heart Writer)(audiobook, out of print)
Investment Clubs for Dummies by Douglas Gerlach (Silent Doug), Angele McQuade (Turtle McQ), and Donald E. Danko
Fabric of the World by AM Jenner (Romana and Heart Writer)
Journal Through the Ages by Mischa Bourgnaes (Romana)

Books about Stamp Carving

The Hand Carved Stamp, by Linda Brennan-Trombadore
Art Stamping Workshop: Create Hand-Carved Stamps for Unique Projects on Paper, Fabric, Polymer Clay and More by Gloria Page
Carve Your Own Itch - Basic Eraser Carving by Bob Clark
The Weekend Crafter: Rubber Stamp Carving: Techniques, Designs & Projects by Luann Udell
Rubber Soul: Rubber Stamps and Correspondence Art (Folk Art and Artist Series) by Sandra Mizumoto Posey
Rubber Stamps & How to Make Them by George L. Thompson
Carving stamps by Julie Hagan Bloch (booklet)(out of print)
Make Your Own Rubber Stamps...From Erasers by Mick Mather (booklet)
Print & Stamp Lab: 52 Ideas for Handmade, Upcycled Print Tools by Traci Bunkers

Books about Other Treasure Hunting

Questing: A Guide to Creating Community Treasure Hunts by Delia Clark and Steven Glazer (other publications for Valley Quest)
A Treasure's Trove: A Fairy Tale about Real Treasure for Parents and Children of All Ages by Michael Stadther
Secrets of the Alchemist Dar: Collector's Hardcover Edition (A Treasure's Trove) by Michael Stadther
39 Clues Series by Various Authors
Treasure and Scavenger Hunts: How to Plan, Create, and Give Them! by Gordan Burgett