Juniper is providing all kinds of free materials on their education portal website. Even more that, Juniper can provide you exam discount after you passed their evaluation exam before you really take VUE exam. For those new to Juniper, it is best place you can learn Juniper and get into Junos world.
so far Juniper has published 21 day one books covered most of its products. The most important and pretty thing is they are completely free. You can use it on iPAD/ iPhone / iPod touch or even Android phone since they are providing multiple format including pdf.