(4) 4-6 As the title suggests, this is the end of a series, the sixth volume about the epic battle between humans and the underworld Styx. Massive surprises, shocking deaths, and (mostly awkward) plot twists await, and fans may leave feeling more confused than resolved. The determined humans hoping to save the world are amiable protagonists and they balance the plot problems.

Reviewer: April Spisak

(4) 4-6 This British import, the fifth in the series, picks up with the brutal Styx infesting England while a scrappy band of humans is still trying to save the world from certain destruction. Die-hard fans of the series will be used to the uneven pace and stilted dialogue; the creepy, monstrous Styx are memorable enough to compensate for the writing flaws.

Reviewer: April Spisak

(4) 4-6 This fourth book follows aptly named Will Burrows (Tunnels, Deeper, Freefall) and his friends as they traipse back to the world at Earth's core and to Topsoil. Though the story line attempts to follow too many characters--including clever heroes and even more interesting villains--the book's fast-paced action will sustain fans. Readers are again left hanging off a cliff at the end.

Reviewer: Jenn Matters

(4) 4-6 Illustrated by Brian Williams. Hero Will (Tunnels, Deeper) falls further--literally--into the secrets of the underground society where he was born. Meanwhile, the evil Styx plot to destroy all "Topsoilers." With educational tidbits dropped into the text, the story drags. Some interesting (if improbable) closing twists may grab series fans.

Reviewer: Claire E. Gross

(4) 4-6 Banished by the restrictive underground society of the Colony (discovered in Tunnels), Will explores the deadly Deeps with his brother Cal and friend Chester. Meanwhile, the sinister Styx hunt him and plan a horrifying biological attack on the "Topsoil" world. The plot has too many red herrings and near-misses to sustain tension, but the action is nonstop.

Reviewer: Claire E. Gross

(4) 4-6 Illustrated by Brian Williams. While pursuing his hobby of underground exploration, fourteen-year-old Will and his best friend are taken prisoner in the oppressive Colony, policed by the sinister, merciless Styx. The innovative underworld setting will stimulate readers' imaginations, but while adventure-lovers will appreciate the twisting plot, they may lose patience with the slow beginning and endless similes. Occasional shadowy, sketchlike illustrations accompany the text.

Reviewer: Claire E. Gross