This section is from the book "The Law Of Real Property and Other Interests In Land", by Herbert Thorn Dike Tiffany. Also available from Amazon: A Treatise on the Modern Law of Real Property and Other Interests in Land .
Sec. 659. General considerations.
660. Express charges on land.
661. Agreements for security (equitable mortgages).
662. Lien for improvements.
665. Express lien of grantor.
667. Vendee's lien.
At common law there was no lien upon a thing owned by one person in favor of another except when accompanied by possession and, furthermore, there could be no lien on land, but only on things of a personal nature.1 In equity, however, there are certain classes of rights in regard to land, as there are in regard to personalty, not based on possession, yet of a character analogous to common-law liens, and known as "equitable liens." These rights involve a personal obligation upon the owner of land, which equity will enforce against the land, ordinarily by a decree for the sale thereof, and which will follow the land into whosesoever hands it may pass, until it reaches those of a purchaser for value without notice.2