Who must file. Generally, the amount of income you can receive before you must file a tax return has increased. Table 1 shows the filing requirements for most taxpayers.

Exemption amount. The amount you can deduct for each exemption has increased from $3,300 in 2006 to $3,400 in 2007.

Exemption phaseout. You lose part of the benefit of your exemptions if your adjusted gross income is above a certain amount. For 2007, the phaseout begins at $117,300 for married persons filing separately; $156,400 for single individuals; $195,500 for heads of household; and $234,600 for married persons filing jointly or qualifying widow(ers). However, in 2007, you can lose no more than ⅔ of the amount of your exemptions. In other words, each exemption cannot be reduced to less than $1,133.

Standard deduction. The standard deduction for most taxpayers who do not itemize their deductions on Schedule A of Form 1040 is higher in 2007 than it was in 2006. The amount depends on your filing status. The 2007 Standard Deduction Tables shown near the end of this publication as Tables 7, 8, and 9 can help you figure the amount of your deduction.

Itemized deductions. Some of your itemized deductions may be limited if your adjusted gross income is more than $156,400 ($78,200 if you are married filing separately). However, in 2007, the amount by which these deductions are reduced is only ⅔ of the amount of the reduction that otherwise would have applied. See Who Should Itemize, later.

Exemption for housing person displaced by Hurricane Katrina expires. The $500 exemption for housing an individual displaced by Hurricane Katrina, which was allowed for 2005 and 2006, is no longer allowed.

Qualifying relative. You may be able to claim an exemption for a child whose parent is not required to file a tax return. See Not a Qualifying Child Test.

Taxpayer identification number for aliens. If you are a nonresident or resident alien and you do not have and are not eligible to get a social security number (SSN), you must apply for an individual taxpayer identification number (ITIN). Your spouse also may need an ITIN if he or she does not have and is not eligible to get an SSN. See Form W-7, Application for IRS Individual Taxpayer Identification Number. Also, see Social Security Numbers for Dependents, later.

Photographs of missing children. The Internal Revenue Service is a proud partner with the National Center for Missing and Exploited Children. Photographs of missing children selected by the Center may appear in this publication on pages that would otherwise be blank. You can help bring these children home by looking at the photographs and calling 1-800-THE-LOST (1-800-843-5678) if you recognize a child.

This publication discusses some tax rules that affect every person who may have to file a federal income tax return. It answers some basic questions: who must file; who should file; what filing status to use; how many exemptions to claim; and the amount of the standard deduction.

Who Must File explains who must file an income tax return. If you have little or no gross income, reading this section will help you decide if you have to file a return.

Who Should File will help you decide if you should file a return, even if you are not required to do so.

Filing Status helps you determine which filing status to use. Filing status is important in determining whether you must file a return, your standard deduction, and your tax rate. It also helps determine what credits you may be entitled to.

Exemptions, which reduce your taxable income, are discussed in Exemptions.

Exemptions for Dependents explains the difference between a qualifying child and a qualifying relative. Other topics include the social security number requirement for dependents, the rules for multiple support agreements, and the rules for divorced or separated parents.

Standard Deduction gives the rules and dollar amounts for the standard deduction — a benefit for taxpayers who do not itemize their deductions. This section also discusses the standard deduction for taxpayers who are blind or age 65 or older, and special rules for dependents. In addition, this section should help you decide whether you would be better off taking the standard deduction or itemizing your deductions.

How To Get Tax Help explains how to get tax help from the IRS.

This publication is for U.S. citizens and resident aliens only. If you are a resident alien for the entire year, you must follow the same tax rules that apply to U.S. citizens. The rules to determine if you are a resident or nonresident alien are discussed in chapter 1 of Publication 519, U.S. Tax Guide for Aliens.