This book focuses on the interaction between embedded devices and other computers on the Internet, using standard web protocols. Its examples mostly use basic sensors and actuators, so it is unnecessary to buy much additional hardware besides an inexpensive computer board. Here is a list of things you need to run all the examples in this book:
A Netduino Plus board (http://www.netduino.com/netduinoplus)
A micro USB cable (normal male USB-A plug on PC side, male micro USB-B plug on Netduino Plus side), to be used during development and for supplying power
An Ethernet router with one Ethernet port available for your Netduino Plus
An Internet connection to your Ethernet router
An Ethernet cable for the communication between ...