Pratiyogita darpan series is best for studying competitive exams and also for extra information. They publish books in series like ptiyogita darpan physics and chemistry, pratiyogita darpan indian governance and polity, pratiyogita darpan current affairs series. And also current affairs series is most important to read. Topics are covered in a series manner. There is complete explanation to every concept. No stone is left unturned by them in publishing these books. These books are very much important to read. Every data is up to date and every chapeter is given in unique way. They also give subjective type questions in every series for upsc candidates. Previous year papers, upcoming exams, model tests etc. Are also given there for more practise. Static gk is given in every monthly book. So these books are value for money and I would suggest you to have it.