The second rule of the House of Representatives concerns other officers and officials. Unlike the Speaker - who, by convention is a member of the House (the Constitution does not restrict it to members - and in fact in 105th Congress two former members were nominated), the other officers are non-members. The rule distinguishes between official elected by the House
and Offices, whose head is appointed. The Elected Officials are
The Clerk - duties are related to the conduct of House business, they are further described here.
The Sergeant at Arms - responsible for maintaining order and security. A factsheet is available here
Chief Administrative Officer - deals with operation and financial matters of the House. More details here
Chaplain - officers a prayer at the start of business, and some pastoral responsibilities. Further details here.
The Offices are
Office of Inspector General
Office of General Counsel - provides legal assistance and representation to the House
Office of the Historian.
In addition statute provides for the following offices
Government Accountability Office (GAO)
Office of Compliance
Office of Legislative Counsel
Congressional Budget Office (CBO)
Office of the Law revision Counsel
Office of the Parliamentarian
For a list of other House offices, commissions, and joint entities go here.