As many as 22.2 million U.S. households comprising about 56 million adults are unbanked. Thisstaggering figure points to a crisis in the bifurcated financial services world where some consumers do not have access to mainstream financial institutions. These households are disproportionately lower-income and minority. Households that do not have bank accounts are disadvantaged in several ways. They spend up to three times as much for basic services using check cashers than consumers with accounts at mainstream financial institutions. Unbanked consumers also lack access to instruments like savings accounts that encourage modest savings. Further, the unbanked may not be able to establish a credit history, which has implications for future credit applications and for employment and insurance coverage. This report, "The Foundation of Asset Building: Financial Services for Lower-Income Consumers", describes some of the best practices in the banking industry to reach low-income, unbanked consumers. These practices include affordable checking or lifeline accounts with account opening criteria and other features that are appropriate for lower-income consumers, innovative financial literacy programs, and creative outreach and marketing strategies. This report explores the financial sustainability of these account products and observations from the bankers on strategic factors of success. An inventory of lifeline banking resources comprises the last section of this report. This report profiles the Acceso Popular Account at Banco Popular de Puerto Rico, Cash and Save Program of Union Bank of California, First Bank of the Americas in Chicago, First Interstate Bank in Montana and Wyoming, and Wells Fargo Bank Wisconsin's participation in the Get Checking Program. The case studies reveal that lifeline banking does more than reduce the number of unbanked consumers; it can also be financially sustainable for the bank. Our basic finding is that banks with a commitment to reach unbanked or under-banked households can do so effectively and efficiently. Some financial institutions claim that it is not financial sustainable to serve such consumers and communities. However, the banks profiled here have demonstrated that with energy and creativity, it is possible to provide retail banking services to people previously considered unprofitable customers.