The authors provide a unified analysis of taxation and taxpayer education when individuals have an incomplete understanding of a complex tax system. The analysis is independent of whether income is earned legitimately, or by avoiding or evading taxes. In this sense, learning about tax minimisation strategies (tax manipulation) is isomorphic to learning about tax rates. The government in this model balances a trade-off - a better understanding of the tax system potentially allows taxpayers to optimise more effectively, but also affects government revenue. Optimal taxpayer education and the optimal amount of redistribution can both be characterised by aggregate sufficient statistics, which do not require information about how biases or behavioural responses vary across the decision margins. The authors provide similarly simple rules for how tax rates on different income-generating activities should be set relative to each other.