Forget the binary between fiction and guides; the true source of inspiration for travel is often word of mouth and shared experience.
My patients don't base their destination choice on a novel, but rather on what a friend told them or on a social media post.
A paper guide often comes after, as a pragmatic check, for logistical aspects like hotels or restaurants.
The first spark is usually an informal conversation, an enticing photo, or even a cooking show that sparks the idea, not a book or a guide initially.
For example, after dinner, a friend talks about their trek in Patagonia, and it's this authentic discussion that triggers the desire, long before opening a guide.