Merlin, a fictional visitor from the Andromeda Galaxy, Planet Omniscia, has been friends with many of the most important scientific figures of the past including Kepler, da Vinci, Magellan, Doppler, Einstein and Hubble. In this delightful tour of the galaxies, Merlin often recounts his conversations with these historical figures in his responses to popular astronomy questions asked by adults and children alike. Merlin's well-informed answers combine a unique combination of wit and poetry along with serious science explained in refreshingly clear, reader-friendly language. Dear Merlin: Can a person cross our galaxy in a spaceship during one human lifespan? Merlin: In 1905, Merlin's good friend Albert Einstein introduced the "Special Theory of Relativity," which predicts that time will tick slower and slower the faster you travel. Were you to embark on such an adventure you could conceivably age as little as you wish, depending of course, on your exact speed. The problem arises when you return to Earth, which will have moved several hundred thousand years into the future and everyone will have forgotten about you. A skywatcher's book for lovers of the universe by one of its greatest lights.