The Boy Who Disappeared (#1 Switchers, 2nd ed.)
Rodney Rowbottom feels alone. His mother treats him like a baby and his father, a scientists in the field of genetically modified crops, is too busy to spend time with him. At school, Rodney is stalked by the local bully, Ben Houlihan, and picked on because of his habit of fading.
Then Rodney meets Mrs Strangeways and his life changes. She shows him the reason for his fading and he discovers the parallel universes Llandringodd and Llondieval, both terrible places. He finds himself embroiled in adventures he'd never imagined. Is Earth following in Llandringodd's dark footsteps? Will he escape with his life?