Most of us are familiar with the Milky Way. We may be lucky enough to live in a dark location and can see the misty band of light that stretches across the sky (see Fig. 1.1). Others may live in an urban location and so can only glimpse the Milky Way as a faint hazy patch that envelopes several constellations. But how many of us make a point of observing the Milky Way as a celestial object in its own right? Rather few, it seems, which is a pity as it holds a plethora of wonderful delights, ranging from deeply colored double- and multiple-star systems to immense glowing clouds of gas and mysterious dark nebulae that literally blacken the sky. It also holds quite a few star clusters that literally look like diamonds sprinkled on black velvet, not to mention the occasional neutron star, black hole and possible extrasolar planetary system! In fact, you could spend an entire career observing the Milky Way.
