The book offered to your attention, is dedicated to unmanned underwater vehicles (UUV). The UUV family is known to have two separate branches: the Remotely Operated Vehicles (ROV) and Autonomous Underwater Vehicles (AUV). Each branch has its advantages and limitations, and specific tasks. The difference between AUVs and ROVs is that AUVs employ “intelligence”, such as sensing and automatic decision making. They have predefined plan of operations in its “mind” allowing them to perform tasks autonomously. ROVs are controlled remotely by a human with the help of communication links on the basis of tether (cable, fiber optic, etc). However, the application of AUV technology to ROVs (transformation them into “smart” ROVs) is decreasing the differences between the branches. Originally there was the word "intelligent" at the book's title, which as it seems to me, correctly reveals tendencies of UUVs evolution. So, AUVs are the main theme of the most articles included in the book.