The most widely recommended of all books is “Techniques of Crime Scene Investigation” by Barry A. J. Fisher. This book is widely considered one of the best on Crime Scene Investigation. Reading this book will give you a great deal of knowledge on crime scene investigation before you enter the field.
Another good book is “Crime Scene Evidence: A Guide to the Recovery and Collection of Physical Evidence”, written by Mike Byrd.
If you have not had any courses on photography, you might need a good photography book like “The Crime Scene and Evidence Photographer’s Guide” by Steven Staggs. It goes beyond basic photography and into the specifics of crime scene photography including step-by-step instructions for photographing crime scenes and evidence, as well as example photographs for different situations.
Fingerprints are an important part of crime scene investigation, so you may also want to read “Introduction to Fingerprint Comparison”.
These books will give you a great advantage when applying for a position as a CSI. It isn’t necessary to read every single book, but the more you read the better. Having studied the field on your own will definitely make you stand out as a prime candidate when you apply for a CSI job.