Handbooks do vary, but their aim is to provide useful information about the organisation you work for and to explain terms and conditions of employment.
These may include:
general information about the organisation;
employment information, such as information on individual conditions of employment, maternity leave, adoption or shared parental leave, the sickness scheme, flexible working, bereavement leave and any specific company rules;
organisational policies and procedures around, for example, training, equal opportunities, time off for trade union activities, grievance and disciplinary procedures, and any collective bargaining arrangements; and
special benefits or services offered to employees, such as occupational health provision, canteen facilities or staff discount schemes.