PrefacePerhaps, the most important head of income under the Income Tax Act is “Profits and Gains of Business or Profession”. Chapter IV-D of the Income Tax Act deals with the same. The terms ‘business’ and ‘profession’ are defined in clauses (13) and (36) of section 2, respectively. Sections 28 and 29 of Chapter IV-D are the related charging sections and the rest of the sections of this Chapter beginning with section 30 and ending with section 44DB, happen to be the computation sections. These provisions are the most frequently used ones, for obvious reasons. Their clear, correct and purposeful understanding is paramount for all tax advisors, tax administrators and the tax payers. The present work is an attempt to help all categories of users in the attainment of this all important objective.As the law governing the profits and gains of business or profession is complex enough as to require particularly comprehensive treatment, we have presented the subject matter in eleven practically self-contained books dealing with a particular aspect each. The scheme of presentation of the subject matter is thus as under ΓÇöBook 1 titled “Business, Business Income, Business Losses” contains Four Parts, namely ΓÇöPart ABusiness & Profession [Sections 2(13), 2(36)]Part BBusiness Income [Sections 28, 29, 43(1), 43(5) & 43CA]Part CBusiness Losses [Section 28]Part DIllustrative Case StudiesBook 2 titled “Depreciation and Investment Allowance [Sections 32, 32AC, 32AD, 38, 41(2), 42, 43(1), 43(3), 43(6), 43A, 43C]” contains Nine Parts, namely ΓÇöPart AGeneral Issues and OverviewPart BAssets Entitled to DepreciationPart CPower Companies, Additional Depreciation, Terminal Allowance, Etc.Part DConditions Precedent for Allowability of DepreciationPart EDepreciation RatesPart FComputational AspectsPart GMiscellaneous IssuesPart HUnabsorbed DepreciationPart IInvestment Allowance [Section 32AC & 32AD]Book 3 titled “Business Deductions” contains Three Parts, namely ΓÇöPart ADeduction Under Sections 30 & 31Part BDeductions Under Sections 33AB to 35EPart CDeductions Under Various Clauses of Section 36Book 4 titled “Residuary Business Expenditure Allowable Under Section 37(1)” contains Ten Parts as under ΓÇöPart AGeneral Principles as to AllowabilityPart BExpenditures Not Allowable Under Section 37(1)Part CExpenditures Vis-a-Vis Setting Up, Acquisition and Protection of BusinessPart DFunds Raising ExpenditurePart EExpenditure Vis-a-Vis Running of BusinessPart FPayments Against Statutory ObligationsPart GPayments Vis-a-Vis EmployeesPart HExpenditures Specific to Particular Kinds of AssesseesPart IYear of Allowability of Expenditure and Related IssuesPart JCase Studies Vis-a-Vis Some Important IssuesBook 5 titled “Business Disallowances” contains Four Parts, namely ΓÇöPart ADisallowances Under Sections 37(2B) and 40(a)(i) to 40(a)(v)Part BDisallowances Under Sections 40(b) and 40(ba)Part CDisallowances Under Various Clauses of Section 40APart DDisallowance Under Section 43BBook 6 titled “Presumptive Incomes [Sections 44AD to 44BBB]”Book 7 titled “Maintenance of Books of Accounts, Accounting Method and ICDS Implications” comprises Three Parts, namely ΓÇöPart ARequirements as to Maintenance of Books of Accounts [Section 44AA]Part BMethod of Accounting [Sections 145, 145A]Part CIncome Computation & Disclosure Standards [ICDS]Book 8 titled “Tax Audit”Book 9 titled “Miscellaneous Issues Vis-a-Vis Computation of Business Income [Sections 14A, 42, 43D, 44, 44A, 44C, 44D, 44DA & 44DB]”Book 10 titled “Computation of Business & Professional Income : Illustrations”Book 11 titled “Specified Domestic Transactions [Sections 92, 92BA, 92C to 92F]”The above user friendly classification of the subject matter coupled with appropriate groupings under various parts of the related book would help a lot in taking away the rigour out of the so widely used and comprehensive a topic. The readers would find it convincingly plain, simple, useful and practical guide book on a subject which is to be dealt with by them on day to day basis. This comprehensive work would prove to be user friendly due to its simple and scientifically devised treatment, apart from its unique presentation.The basic strength of the book lies in the incorporation and coverage of a large number of case law, practically all those that are available and also, to a certain extent, useful. This includes all courts’ judgments and all the decisions of Tribunal Benches.All the important Circulars, Notifications, Instructions, etc. relevant to the subject matter have also been incorporated at the relevant places so as to make the treatise most up-to-date ever.One more attraction is incorporation of various Case Studies providing useful solutions to day-to-day problems being and likely to be faced by the tax practitioners.Above all, our huge experience of authorship has enabled us to confine the subject matter to a single, though a Mega Volume, without loss of comprehensiveness in any of the inputs, which makes this product a unique facility for one and all.Lawwise updation for Assessment Year 2017-18 also will be made available through our Website via Reader Specific URL Code provided on Page (iii) of this Book, which updation will continue till December 2016 end and shall also comprise discussion of any path breaking or very important decisions if delivered and available till then. The website as of now incorporates Full Reports with Head Notes of practically all (as many as 9753) the Courts Judgments/Tribunal Orders cited or discussed in the book, apart from reproduction of all Circulars, Notifications, related Statutory Provisions and Rules referred to in the treatise.We acknowledge the contribution of one of our Associate Authors CA. Manoj Gupta, BSc, FCA for having prepared the Books 2, 8 and 11 of this treatise.Though we have tried not to leave any stone unturned to make this treatise user friendly and informative, however, we will be thankful for any constructive suggestions for further improvement as and when the occasion arises.