Palantir was one of the first companies I interviewed with, and I felt that throughout the process, they were highly professional. I went through two phone interviews about a week apart followed by an onsite interview. The phone interviews were pretty simple (test an eReader, test a smartphone), and the onsite was straightforward as well. I interviewed with three people, all of whom asked me to test various things. After that, lunch and a product demo. After the product demo, they pulled aside a few people for additional interviews. The rest of us got shirts. I received the rejection a week later.