Fortey is a Trilobite expert. I know this because he wrote another book before this one called Trilobite! Eyewitness to Evolution. I personally love his excitement.
What's a Tri-lo-bite and why is Fortey so obsessed with them?
Trilobites are a fossil group of extinct marine arthropods and form one of the earliest known groups of arthropods.
I'm lost, what are arthropods?
An arthropod is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages.
They're so ugly and they look like this...
Trilobites are the state fossils of Ohio, Wisconsin and Pennsylvania.
American Museum of Natural History has an entire website dedicated to Trilobites.