domain registration – TLD status .book

According to Wikipedia, .book is an existing top-level domain. However, it is apparently not yet available for registration. I was able to learn that Amazon had bought the rights in 2014, but I can not find any information on the start of the land rush.

Is there a way to know when the landrush for .book will start? Is the timing of this transaction entirely at Amazon, or are there, for example, ICAAN Regulations specifying when to start licensing these domains?