Albert Einstein and his soon to be wife Mileva engaged in premarital sex. This alone was frowned apon at the time in and around
Switzerland, and when Lieserl was born in
1902, she was a downright
disgrace. She was given up for
adoption before the wedding of her parents a year later.
It is due to this that little is known about Lieserl Einstein, and mystery still surrounds much of her past today. She is the focus of innumeral books (as a warning, a large number of these are largely fictional, regardless of how they are marketed), and even one or two television documentaries.
Lieserl is also the name of the main character in a short story by Stephen Baxter, which is included almost complete in the initial chapter of his book Ring.
I've been asked why this writeup wasn't under Lieserl Einstein. The fact is that Lieserl is a kind of early 20th century Anastasia; we'll probably never be totally certain of her fate. She is generally refered to simply as Lieserl, with the surname ommited since, after all, she was put up for adoption.