This handbook is intended to provide technical information for personals who wish to understand the photovoltaic or PV application of solar energy. This handbook can be used as a comprehensive reference resource and can be read in its entirety. It contains detailed information on the basics of solar electric components and systems, solar system design, as well as end to end costing for the rooftop grid-connected solar system. Even a full reading of this handbook is not intended to convey nor does it mean that an individual is then fully trained, qualified, or certified in the design or the installation of the PV system. All local, state and central regulations governing licensing and permitting of individuals and organizations engaged in PV work must be followed before performing any activities described in this handbook This handbook includes a detailed explanation and system design for a 4 kW single-phase grid-connected rooftop solar system. The system cost is calculated based on the average price and may vary depending on local site conditions and customer requirements.