Researchers at the University of Wisconsin have shown that meditation improves your concentration (.pdf). The minds of us Westerners suffer from something called "attentional blink," which makes our minds to "blink" after perceiving some important fact, causing us to miss other pieces of information presented directly after it.
Attentional blink can be operationalized and tested pretty effectively. Heleen Slagter and her colleagues at the Center for Affective Neuroscience at the University of Wisconsin tested subjects before and after three months of training in Vipassana meditation, and found that their attentional blink was significantly reduced after they had begun meditating. That is, they were able to concentrate more evenly, not in little spikes, and were therefore able to perceive and retain more information from their environment.
You may be asking yourself: "Is there a clear, accessible, jargon-free book that can explain Vipassana meditation?" Why it just so happens that Bhante Henepola Gunaratana has written it. It’s called Mindfulness in Plain English. The author is a Sri Lankan Buddhist monk who’s also extensively trained in Western philosophy, and introduces beginners to Vipassana meditation in clear, lively prose. No knowledge of Buddhism required, although if you become curious about it after meditating for a while, Bhante G. has got you covered there as well.