Samsung Galaxy Nexus is the first handset running Android Ice Cream Sandwich and was announced back in October 2011. The device was made available some time in November 2011. Like any other Android version, ICS running on Galaxy Nexus is also available for customizations in the form of rooting, unlocking, installing custom firmware and much more. But if you are a beginner and not sure how to get started with this, then probably you can try the free app Galaxy Nexus Root Toolkit, which is an all-in-one toolkit to root, unlock, relock, unroot and do many more things with your Galaxy Nexus. Galaxy Nexus Root Toolkit makes your task even easier than before.
Using this free utility, users will be able to easily unlock the bootloader inside the phone, re-lock it if needed, root and unroot the device for any customizations, back up and restore apps and data in your phone, or flash the smartphone to stock firmware, in case you are using a custom firmware. The app has easy to use interface and needs all the drivers for Samsung on Windows.
There are two flavors of the tool available, one meant for the GSM version of Galaxy Nexus, while the other is for the LTE-capable version of the device. More information and detailed instruction on the utility can be found on the Galaxy Nexus Forum.