This course explores electrical circuits in the quantum regime, with an emphasis on superconducting qubits and their applications in quantum computing. Essential tools from quantum optics, circuit theory, and superconductivity are introduced to analyze a range of experimentally relevant systems. Topics include Josephson-junction-based qubits, parametric couplers and amplifiers, and quantum state transfer mediated by propagating microwave photons. Students will learn to model circuit Hamiltonians, design elementary circuits for gate operations and qubit readout, and understand the physical origins of quantum decoherence in solid-state systems. The course is intended for graduate students and advanced undergraduates with prior exposure to quantum mechanics and basic circuit theory.