Problems.

Although a relatively small package, Lifelines is quite complex. Thus, you do have to spend some time practicing how to use it and reading the manual.

And some things are not in the manual. After book-latex.ll generates a TeX file and you run LaTeX on it, the latter complains that it cannot find the file tree.tex. This is not normally in TeX distros. If you read the comments at the beginning of book-latex.ll (thank god for open source!) you find you have to go out and get tree.tex. Similarly, when I first ran LaTeX on raw.tex it complained that the command \spouse was undefined. This was easily fixed by editing raw.tex and inserting a trivial line
\newcommand{\spouse}[1]{{\it #1}}
which, as anticipated, made LaTeX happy.

Overall, the end result makes the effort worthwhile. The original program was written by one person, T. Wetmore, for his own use, but now it has migrated to SourceForge. It also has some aspects of "work in progress" but I expect we shall see some fixing of things that are broken.