It depends how far you want to go. If your just after a few tips then those books will help. However if you want to understand how to design things properly and make they really efficient then you need to look at Materials engineering/mechanics maths . The maths have a lot of real world application and will help you understand how and why certain shapes and geometries are stronger and where things may break first. Once you've got that down then you can really start looking into why carbon fiber can be more useful than aluminium or other materials in certain structural applications.

Dave.