What are the best beginner books to understand the foundations of Buddhism that everyone should read?
The most basic book for all of Buddhism would be “What the Buddha Taught” by Walpola Rahua. Also a good survey of Buddhism might be “Buddha” by Karen Armstrong.
Buddhism is so diverse and may seem so different to a person looking at Buddhism for the first time. There are so many schools, sects and subsects (each proclaiming to have the true path). Actually we each have to find our own path, thus, there are so many sects.
For our sect of Pure Land Buddhism, called Jodo Shinshu in Japanese and translated as Shin Buddhism, I would suggest “Ocean” by Kenneth Tanaka (copies are available in the MBT Bookstore) and “River of Fire, River of Water: An Introduction to the Pure Land Tradition of Shin Buddhism” by Taitetsu Unno.
Gassho (with palms together), Rev. Ron