What are solvolytic displacement reactions?

High school student here, I recently purchased a book titled: "Solvolytic Displacement Reactions" by Andrew Streitwieser published in the early 1960's. I found it at a book store and it looks like one of those incredibly valuable (in terms of knowledge) books. I tried reading the first few pages (have a basic background in chemistry) but I do not see "the big picture". What are solvolytic displacement reactions, how are they used and what are they used for?

A book could be written on this subject!

A solvolysis reaction is an $\ce{S_{N}1}$ reaction where the solvent acts as the nucleophile and replaces the leaving group. The following reaction is a solvolysis reaction run in ethanol.

I suspect there are some industrial uses of solvolysis reactions and they have been used in labs and by drug companies as a step in a synthetic sequence to prepare some complex molecules.

But I suspect the biggest contribution from the study of solvolysis reactions is the impact they have had on our understanding of carbocation chemistry. From our study of solvolysis reactions we have learned how and why some carbocations rearrange before being captured by solvent.

While studying such rearrangements the solvolysis of the norbornyl system was examined.

It turns out that

• norbornyl compound 1 solvolyzes several hundred times faster than compound 3 - why?
• if compound 1 is prepared optically active, the products are racemic - why?
• If compound 1 is radiolabeled, the label is scrambled in the products - why