This handbook has been designed for the aspirants of IES, GATE, PSUs and other competitive examinations. This specialized book for Computer Science & IT has been divided into 10 units each containing detailed theoretical content. Key terms in each unit have been given with their definitions. Every topic is taken up separately along with Key Points and notes. All the formulae used have been well illustrated and diagrams have been given for theoretical analysis. This book covers almost 100% syllabus of Computer Science & IT making it the only book for multipurpose quick revision and ensuring success in IES, GATE, PSUs and other competitive examinations. Appendix has been given at the end of the book