Understanding Babies Who Cry Inconsolably

One of the most stressful parts of caring for our baby daughter was when she cried and nothing we did helped. It can lead even the strongest parent to tears!
We knew babies cried a lot but we didn't know how helpless we would feel when we couldn't comfort her. We also didn't know how common this type of crying is for all babies.
The Period of PURPLE Crying acronym captures what is going on:
Peak of Crying - Your baby may cry more each week, the most in month 2, then less in months 3-5.
Unexpected - Crying can come and go and you don't know why.
Resists Soothing - Your baby may not stop crying no matter what you try.
Pain-like Face - A crying baby may look like the are in pain, even when they are not.
Long Lasting - Crying can last as much as 5 hours a day or more.
Evening - Your baby may cry more in the late afternoon and evening.
Dr. Ronald Barr provides an excellent explanation of the PURPLE crying period in this video: