Leslie Cantwell was a person who collected things that were important to them, like a hobby. The Leslie Cantwell Collection refers to all the things that they collected during their life.
Think of it like when you pick up rocks or leaves on a nature walk and keep them in a jar as a keepsake. Leslie Cantwell liked to do that too, but with lots of different things like books, art, clothes, and other items that they thought were special.
Their collection is important because it gives us a glimpse into what things were like during their lifetime, and what they thought was interesting or valuable. It helps us understand the past and remember people like Leslie Cantwell who were passionate about preserving pieces of history.