Accessible Science Writing 

Bonk

First book I read by Mary Roach. This book explains a lot of the oddities and barriers in the scientific study of sex.
Scientists often are not good writers, Roach was a travel writer first thus her writing is dynamic and easy to get into.

Stiff

Excellent book examining what happens to bodies after death. This can even include dissection, or becoming a crash test dummy.

Gulp

This book looks at the science of digestion and how difficult it has been to study throughout history. I mostly remember a section on how prisoners smuggle... everything really.

Packing for Mars

I haven't read it yet but I'm sure I should.

Spook

In this book Roach examines how others have looked into the afterlife attempting to use science.

Grunt

Roach's most recent book I looking forward to reading it.