Subterranean alternate-cultures are a fascinating little niche in modern literature. However, "Neverwhere" never attains the characterization or depth of Neal Shusterman's "Downsiders," combining sketchy characterization with truly worthy chills.
Except for an odd fortuneteller's warning, Richard Mayhew appears to have everything going well. He has a good job and a fiancee whom he loves -- until the day he and his fiancee stumble over a young woman bleeding in the street from a stab wound. He carries the girl, who calls herself "Door" and refers to the city as "London Above," back to his apartment, fixes her up, and helps her back to wherever it is she came from.
But a sinister pair came by while she was recovering, the deliciously evil and creepy Mr. Croup and Mr. Vandemar. And the sudden loss of his identity quickly drives Richard deeper into "London Below," a shadow world of rat-girls called Anesthesia, body-guardians, the bizarre marquis, and a hideous Beast of London whom he must try to battle...
I have heard exceptional things about Neil Gaiman, and enjoyed the beautifully-written "Stardust." However, perhaps this was an "off" item for Gaiman; there isn't much charm or interest in this story. Part of that stems from the lead character, Richard: He's a limp dishrag of a character, who reacts blandly to every situation, no matter how fantastical or terrifying it is. When his friends don't recognize him and strangers don't see him, his noticeable emotion is not frustration and anger, but a sad "oh well, I guess I'm in trouble." This might not have harmed the book, except that Richard is the lens through which the readers see the story. There are brief exceptions: passages that focus on other characters entirely, which are delightfully written and very spicy.
The other characters are delightful: Door, a slightly off-kilter girl who can "open" doorways through things; Croup and Vandemar, ageless and delightfully, wittily, gruesomely evil (faint of heart: do not read the passage where one of them starts eating a rat), pursuing the heroine with flowery words and playing around with razor blades; Hunter is intriguingly mysterious and engaging; Marquis de Carabas is also intriguing and sometimes amusing.
I found Gaiman's language to be a little too stark: he spends a great deal of time "telling" but not quite enough "showing." The dialogue was good for each character, from the ordinary speech of Richard and Jessica to the choppier words of the people underground. Parents won't want kids reading this book, due to gruesome scenes and sexual passages; "Downsiders" is a better choice for them, another tale of subterranean civilization. It's less fantastical, but an engaging read nevertheless.
"Neverwhere" reaches for excellence but fails to grasp the bar. A nice read only if you have nothing else to do at the moment.