Like me, you may not be aware that 2015 is the official “Year of the Phage”; indeed (also like me), it’s possible you aren’t entirely sure what phages are. Don’t let that stop you: learning about phages — 
bacteriophages, that is — is fascinating. And, since not many laypeople know about them, you’ll find yourself right on the cutting edge of what we currently know about genetics, bacteria, and virus behaviours!
Very generally, bacteriophages are viruses that infect bacteria. As such, they are incredibly tiny (measured in nanometers), and scientists are unsure of how many different kinds there are. They are found everywhere, and their actions are full-on survival-of-the fittest:
“They float about, awaiting a microbial encounter, then attach themselves to their preferred targets using a remarkable array of equipment—arms like grappling hooks, tails like hypodermic needles, fibres like teeth—each of which is perfectly adapted to bind to, and then sneak genetic material through, the bacterial membrane. Once inside the cell, some phages replicate at speed, destroying the host by bursting out of it, like a fungus dispersing its spores. Others are parasitic, integrating their DNA with that of their host. Sometimes they even prov
ide it a benefit of some kind.”
Bacteriophages lurk on the level below bacteria; indeed, as The New Yorker’s Nicola Twilley writes, they can be considered the “puppet masters,” controlling how bacteria operate from behind a curtain.
We’re only just starting to learn how bacteria affect our microbiome and our world; it’s consequently easy to see how little we know about bacteriophages. Forest Rohwer, a San Diego University professor and marine microbial ecologist, has sought to remedy this by publishing “Life in Our Phage World,” a “field guide” of sorts covering the bacteriophages now known to science. His aim is increased general knowledge of the fascinating entities that underpin nearly all known biological processes on earth: “I would like just at least some kids,” he says, “when they see a picture of the phage, to know what it is.”
A PDF of Rohwer’s book can be downloaded for free here. I know what I’ll be reading on the dock with a glass of iced tea this summer — How about you?