What qlot is trying to solve
We have Quicklisp, the central library registry. It made installation of libraries damn easy.
However, what only you can specify is the month of distribution. Which means you have to use all libraries of the same moment and you cannot use a newer/older version of a library for your project.
"local-projects/" or ASDF configurations may be a solution to this problem, but there are a couple of problems.
1) They are not project-local. If you have multiple projects that use the different version of the same library, it would be a problem.
2) They are difficult to fix the version or to update them. If your project need to work on other than your machine, for instance on other people's machine or on servers, the version of depending libraries should be the same.
This is what qlot is trying to solve.
or with Roswell:
ros install qlot
See the documentation !