The most useful thing about Buddhism, if you're not a Buddhist, is that it spent about 2,500 years doing what Western psychology only started doing in the last century: watching carefully how the mind manufactures suffering, and testing what makes it stop. You don't need to believe in rebirth, join a monastery, or accept a single metaphysical claim to use what it found. The core of the tradition is a practical investigation into why your brain generates so much unnecessary misery, and the findings hold up well under modern neuroscience. Researchers studying the Default Mode Network, the circuitry behind that relentless loop of self-referential chatter, reported in 2011 that experienced meditators show measurably lower activity there. Which is roughly what Buddhist teachers meant by "quieting the monkey mind," described a few thousand years earlier and without a scanner.
The books here are chosen for readers who want the practical psychology without the conversion. They come from different corners of the tradition: a Sri Lankan monk who wrote the clearest meditation manual in English, an American nun who turned the collapse of her own life into a practice, an evolutionary psychologist who tested Buddhist claims against lab data, and a Japanese Zen master whose talks read more like poetry than instruction. Several are Western therapists who noticed that their clinical training and Buddhist psychology kept arriving at the same conclusions through different doors.
The tradition is enormous. One good entry point is all it takes.
If you want the science first, start with Wright. If you want the practice, start with Gunaratana or Suzuki. If something in your life has recently come apart and you need a book that speaks to that directly, start with Chödrön.