These may help
"How to Legally Avoid Paying Taxes" (1970) by Barry Steiner. One of the most famous layman-friendly books of its era, it provided everyday Americans with actionable advice on deductions, exemptions, and income-shifting tactics.
"The Rape of the Taxpayer" (1973) by Philip M. Stern. Though more of a critical look at the tax system, it was a massive bestseller that exposed the loopholes the wealthy used, giving everyday readers a roadmap of how the code operated.
"J.K. Lasser's Your Income Tax": Throughout the 1970s, the Lasser Institute published updated, highly practical annual guides designed to be easily read by laymen, full of specific line-by-line instructions and year-specific changes.
"Sylvia Porter's Money Book" (1975) by Sylvia Porter. This comprehensive personal finance guide included heavily referenced, layman-friendly sections on minimizing income, property, and estate taxes. [1, 2, 3]