"Many other scientists and philosophers have specu­lated about whether habitable planets and life might exist elsewhere. As we have seen, the debate has been carried out sporadically for literally thousands of years and remains unresolved at the present time. But this question is now timely and exciting because, as we shall see, astrono­mers are on the verge of being able to answer these questions observa­tionally. If they can manage to do so, and especially if evidence for Earth­-like planets and life is found, the philosophical implications would be profound. Indeed, such a discovery would be no less world­-shaking than Galileo’s proof that the Earth goes around the Sun."
(From How to Find a Habitable Planet)

It contains such helpful chapters as Long-Term Climate Stability, Indirect Detection of Planets around Other Stars, Finding and Characterizing Planets by Using Transits, Direct Detection of Extrasolar Planets and The Spectroscopic Search for Life.

This would have been the perfect book for Lazarus Long and the Howard Families; from Robert Heinlein's 1941 novel Methuselah's Children:

Lazarus faced the crowd. "There's a spaceship hanging out there in the sky, a roomy thing, built to make the long jumps between stars. Why don't we take it and go looking for our own piece of real estate?"

Bertram Hardy was the first to recover. "I don't know whether our chairman is lightening the gloom with another of his wisecracks or not, but, assuming that he is serious, I'll answer. My objection to Mars applies to this wild scheme ten times over..."

After escaping in the New Frontiers, they used Andy Libby's space drive to head for a nearby star.

The type G2, or Sol-type star, toward which they had bent their course years earlier was now less than a light-year away - a little over seven light-months - and it was now possible to infer by parainterferometric methods that the star (ZD9817, or simply "our" star) had planets of some sort.

In another month, when the star would be a half-light year away, deceleration would commence. Spin would be taken off the ship and for one year she would boost backwards at one gravity, ending near the star at interplanetary rather than interstellar speed, and a search would be made for a planet fit to support human life. The search would be quick and easy as the only planets they were interested in would shine out brilliantly, like Venus from Earth; they were not interested in elusive cold planets, like Neptune or Pluto, lurking in distant shadows, nor in scorched cinders like Mercury, hiding in the flaming skirts of the mother star...