One possibility is that you will receive a federal summons compelling you to bring either the completed tax return or your books and record to the IRS office. This summons is backed by the power of the federal courts, which can hold you in contempt if you fail to do so. The IRS can prepare your delinquent tax return for you called a Substitute For a Return (SRF). This is guaranteed to result in a much greater tax than had you prepared your own return. It also makes the taxes at issue non-dischargeable for bankruptcy purposes.