A deed is a document that is the actual conveyance of real estate from one party to another.
I am from Oklahoma and we are still an abstracting state (one of our state congressmen owned a lot of title companies). This means that each property that is bought or sold comes with its own abstract of title which, like Bill stated, is a large 3-4 inch book (usually stored with the title companies). The abstract contains each document that has ever been filed with the County Clerk that pertains to that particular piece of property. i.e. deeds, mortgages, liens, releases, court documents, etc. Therefore, in order to obtain ownership of the property a deed would have to be signed by the current owner of record transferring that ownership to the buyer.
However, the title and title insurance discussion is a little murkier. Generally a title to property can be traced back to the original owner through the title documents filed in the County records, whether in an abstract or electronic filing. These documents are called the chain of title. Like a chain, the documents must link together from each owner to buyer and owner to buyer through time. Each deed must be signed by the owner of record and filed in accordance with the state standards and mortgages must be released by the proper parties, etc.
In Oklahoma, the requirement is that we transfer “marketable title.” This means that when a person has marketable title, they not only have a deed that proves current ownership but that the title is clean and that no other person can claim an interest in the property. In my experience, title insurance does not replace a deed. Title insurance is a title insurance company’s opinion, after reviewing the title documents, that “marketable title” is vested in a particular individual and if another party makes a claim on the property they will defend the title of that individual against that claim. Title insurance is an insurance policy that covers the owner against claims of interest in his property.
I hope this helps.