Tim Sullivan 
Martian Viking [EPUB ebook] 

Hallucination . . . or time travel? One man alone against the cosmos, creating his own reality! Exiled on Mars! Johnsmith Biberkopf escapes from a penal colony on the Red Planet and learns that his hallucinations are real—space and time can be manipulated. Kidnapped by Vikings who have sailed through the continua since ancient times, Johnsmith embarks on an epic adventure, an infinite journey through the multiverse. Facing alien menaces, he learns the terrifying truth about the power of illusion.