Book excerpt: This book focuses on the surface plasmon resonance (SPR) technique covering fibre optic sensor research. It highlights recent advancements in geometric feature-based fibre optic SPR sensors for chemical/biochemical/biosensor applications. The contents also discuss the principle of the SPR sensing technique as well as various designs of fibre optic SPR probes for improving sensor sensitivity. It also includes numerous examples of SPR-based fibre optic sensors with various geometric (such as U-type, taper type, D-type, and interferometric-based) sensors. This volume will be a useful reference to those in academia and industry especially researchers with useful information focusing on fibre optic SPR sensors.