Convergence (Convergence #1)

Urban fantasy by Craig Alanson, first in the Convergence series. Fugitive wizard Kazimir Wolfe roams the country in an RV with Duke, a talking dog inhabited by the spirit of a 3,000-year-old Babylonian sorcerer. As magic collides with the modern world, Kaz – the world's only wizard, and one with barely any power – becomes humanity's unlikely last line of defence against a catastrophic convergence between reality and the Nether realm.