Frederick James Dittmar

This book is pretty to-the-point and limited in scope. It gives you a very little bit about almost every blessed ship in the Royal Navy in WW1: date of launch, builder, fate, pendant numbers, etc. But it has a nice compact form factor and an error rate far below other sources you'd do well to trust (e.g., Conways). If you want the basics, get this book and use it in preference to almost any other source that offers the same information.