Here is a list of qlik literature: Books and literature - you could begin them from the top and if you are already really experienced leave the first two out and take the third and fourth one otherwise I suggest them, too.
To learn QlikView, I suggest you attend QlikView training! I would recommend visiting QlikView Training: How to Add Business Intelligence to review the available courses and get registered.
I would also encourage you to learn Qlik's newest product, Qlik Sense. You can learn about Qlik Sense easily and at your own pace by visiting Qlik Continuous Classroom