To the Sky Kingdom is the English translation of the book upon which the Chinese TV series 'Eternal Love' is based (not to be confused with the different Chinese TV series 'The Eternal Love'!). I had seen and enjoyed that series so was keen to read the novel. 

I was hooked from the very beginning. The prologue was gripping and from the start to the end of the book I never wanted to put it down (forcing myself mainly for necessities like sleep). The writing style worked really well for me, notable especially since the writing in translated works doesn't always hold up so well. 

The biggest difference from the TV show is that the book starts much later on in Bai Qian's life. Events which form major parts of the TV show are essentially summarised in the book as the character reflecting on her past. That isn't the only way that the TV show expands on the book either - there are characters barely mentioned in the book who I loved in the show; plotlines significantly expanded on during the adaptation to TV. In general the book is much more character focused and introspective, with much less attention to things like battles and politics. As it's written in first person, we also see much less of other characters - even the male lead arguably gets less development as Qian isn't always aware of what is happening to him. 

The above isn't a criticism of the book by the way - after all, the book came first and should be judged on its own merits - but I would encourage anyone to watch the show either before or after reading the book as it greatly enhances the story. The story itself isn't actually changed much during adaptation to TV (other than where required by censorship, ie removing any mentions of characters being gay), it's just expanded on to an extent I haven't often seen. 

I really enjoyed this and I hope that the companion book about Qian's niece either is or becomes available in English as I desperately want to read it.