I did not mark for spoilers because the book is >20 years old.
I think my library got this book when I was less than 10. It was one of my favorites as a child, and as an adult, it still pulls those tickles of fancy. I still have those recognitions of the romantic portrayals of how knights should be or act.
This book has at least two storylines with the same people, or nearly the same people. On the one hand, Dan Simmons is working during Christmastime and an out of control truck runs into his van. He has nothing really wrong with him, but he doesn't wake up. His doctor is described and portrayed as really really really wanting order (wondering if there are control issues or OCD in there as an adult) and so leads up to the doctor nearly using Electroshock therapy to keep him from sleeping so long. On the other hand, Dan is hurled into a different land which is more an allegorical land (maybe a differing dimension). He is recognized as a knight by Bliss, the first person he meets in the other land. One of my favorite characters is Napoleon, a chocolate Netherlands Dwarf rabbit, who talks. Dan's quest is aided, or hindered, by people whom he later recognizes when he intermittently wakes from his sleep in "our" world.
Sometimes deep, sometimes silly; a tale of love-at-first-sight where the reciprocal relationship grows because of character instead of just because the characters look beautiful. It also gives an imaginative glimpse into how a person relates to the Bible, how spiritual growth happens, and the spiritual becoming physical.