Scope Management involves controlling what is and what is not in the scope. It consists of the following processes. See also Knowledge Areas - Scope.
|  Plan Scope Management    ||    Planning|
|  Collect requirements/Define scope  ||    Planning|
|  Create Work Breakdown Structure (WBS)  ||    Planning  |
|  Validate scope  ||    Monitoring & Controlling  |
|  Control scope  ||    Monitoring & Controlling  |
According to Rita Mulcahey's PMP Exam Prep Guide, the scope management plan consists of 3 elements: how will scope be planned, executed, and controlled.
The Scope Definition process involves documenting stakeholders needs as requirements and defining a detailed description of the project and major deliverables.
Scope includes both Project Scope and Product Scope. From Wikipedia,
"A martini. Shaken, not stirred."   Sean Connery as James Bond
A common pitfall encountered when collecting requirements is a tendency to focus on the solution rather than the requirements. In this phase, the business should focus on 'the what', not the 'how'.
Remember, James Bond is not writing your requirements.
Creating the Work Breakdown Structure (WBS) involves decomposing the work into smaller components. It is a graphical representation of the hierarchy of the project. The WBS is created by the project manager and the project team and forces the project team to think through all the levels of the project.
According to the Project Management Body of Knowledge (PMBOK), "the WBS can be used to effectively decompose the project scope, to improve estimating, to better control the project execution, and to more accurately verify project completion."
Some WBS guidelines:
Wikipeida provides an example WBS for reference.
Also from Wikipedia, a work package at the activity level is a task that:
A WBS dictionary explains all the WBS components. It's narrative description of each element in the WBS.
Scope Verification is the process in which the project customer verifies and formally accepts the project deliverables. Scope Verification happens at the end of each phase. Do not confuse with the Perform Quality Control, which focuses on correctness of work.
Scope control refers to managing changes to project scope.
Scope creep refers to uncontrolled changes to the project and represents risk to the project.
"I look for ambiguity when I'm writing because life is ambiguous."  Keith Richards
Unclear and ambiguous requirements are a common cause of scope creep. Thus, requirements must be clear and unambiguous, leaving no room for interpretation, and all assumptions must be well documented. Requirements aren't a work of art or rock lyrics, open for interpretation.
"It's not true I had nothing on, I had the radio on."   Marilyn Monroe
Visit the Scope Management Bookshelf to search for books available for purchase.
"Rock Stars as BAs?" as published in Project Connections
Project Scope Management on Wikipedia
WBS on Wikipedia
Project Scope Management Sample Questions
SMART Requirements on Wikipedia