This paper introduces a new type of superconducting qubit called the "transmon," which is designed to be less sensitive to charge noise compared to the Cooper pair box (CPB) qubit. The transmon operates in a regime where the ratio of Josephson energy to charging energy, $ E_J/E_C $, is significantly increased. This design choice leads to a dramatic reduction in sensitivity to charge noise while maintaining sufficient anharmonicity for selective qubit control. The transmon benefits from an exponential decrease in charge dispersion with increasing $ E_J/E_C $, while its anharmonicity decreases only algebraically. This results in a significant improvement in dephasing times compared to the CPB. The transmon is also more robust against other noise sources such as critical current and flux noise. The paper discusses the design and operation of the transmon, its quantum circuit, and its performance in circuit quantum electrodynamics (circuit-QED). It also compares the transmon to other types of superconducting qubits, such as the phase qubit, and shows that the transmon can achieve strong coupling with a transmission line cavity. The paper concludes that the transmon is a promising candidate for the next generation of superconducting qubits due to its improved performance and robustness against noise.This paper introduces a new type of superconducting qubit called the "transmon," which is designed to be less sensitive to charge noise compared to the Cooper pair box (CPB) qubit. The transmon operates in a regime where the ratio of Josephson energy to charging energy, $ E_J/E_C $, is significantly increased. This design choice leads to a dramatic reduction in sensitivity to charge noise while maintaining sufficient anharmonicity for selective qubit control. The transmon benefits from an exponential decrease in charge dispersion with increasing $ E_J/E_C $, while its anharmonicity decreases only algebraically. This results in a significant improvement in dephasing times compared to the CPB. The transmon is also more robust against other noise sources such as critical current and flux noise. The paper discusses the design and operation of the transmon, its quantum circuit, and its performance in circuit quantum electrodynamics (circuit-QED). It also compares the transmon to other types of superconducting qubits, such as the phase qubit, and shows that the transmon can achieve strong coupling with a transmission line cavity. The paper concludes that the transmon is a promising candidate for the next generation of superconducting qubits due to its improved performance and robustness against noise.