Cave Diving Navigation is a well-illustrated review of techniques used by trained cave divers when conducting safe explorations into underwater caves. Numerous photographs are included to balance the text. With 96 pages, the authors' approach in addressing this problematic activity begins with a review of the most basic of tools used by cave divers. The authors are quick to emphasize how local cave dive team navigation practices may conflict with dissimilar underwater navigation routines that are used by visiting cave diver teams. Underwater cave regions worldwide are witnessing a steady increase of recreational cave use, especially those regions with complex underwater passages. It also becomes more common for various teams with dissimilar experience levels to enter popular caves and share the same guidelines and exit markers within a crowd of various teams. This book focuses on presenting a consistent philosophy where all independent teams in a cave can utilize all cave guideline arrangements and a wide variety of navigation markers in an similar fashion. The line of reasoning is simple; we must maintain a reliable path to the exit for each team in the cave. Both authors are recognized for their underwater cave explorations in many countries. As professional divers they are also respected in their skills when exposing students safely to a variety of cave diving educational and environmental situations.
The first chapters begin with a nuts and bolts overview of the types of guidelines that are used by all cave divers. This includes a discussion of construction and color of guidelines followed by specific applications for these types of cave guidelines. For example guideline colors may be reserved for specialized temporary, emergency, or permanent line use in different sections of an underwater cave. Many common and specialized knots are described and noted for their best applications. I was impressed by the detail used in the knot illustrations. North American cave divers may not be familiar with some of the described knots or some of  their names. The reader should keep in mind that the book is designed to have an international appeal. Sump diving anchor types, their use, and the most appropriate knots for these anchors are also considered. Two styles of permanent knots used for cave survey are described. One survey knot style incorporates a set of knots used to orient a diver towards the cave exit disqualifying the use of modern plastic markers. Obviously this knotting system may have fatal drawbacks in multi-entrance caves.
The following two chapters contain a lengthy dialogue on the use and installation of permanent and temporary markers. Underwater cave navigation is complicated and occasionally a lethal activity if the team is uncertain on their closest exit to the surface. Cave navigation requires a thoughtful blend of permanent and temporary guidelines with a more conscientious sprinkling of permanent exit markers and non-directional (temporary) guideline markers.
Multi-team scenarios are offered when sharing guidelines in congested caves. This ultimately leads to a philosophy and use of either permanent or temporary ("removable') markers.
Cave Navigation is designed to be studied by all recreational divers who share caves with international divers with different experience levels. It is not a manual for cave exploration, but a means to dive safely in our ever crowded underground wilderness. It suggests we sacrifice a bit of independence as cave divers for the good of all. Permanent exit markers must be left undisturbed while dive teams should deploy temporary markers and reels in a certain manner. The concepts presented in the book deserve a review by all cave divers.

Jim Coke