Planning for a Diving PhotoJourney
This eBook indicates the preparation needed for the planning for any Diving PhotoJourney: what to take in terms of underwater as well as camera gear, planning tips on dive resorts, etc,
The PDF eBooks:

•  a 95 megabyte 25 page high resolution image PDF document 
•  a 29 megabyte 25 page ebook resolution image PDF document      <-- Best choice.
•  a 3.6 megabyte 25 page screen resolution image PDF document 

The PDF has many internal cross-references as well as 85+ links to external sites.