This book by Manfred Knebusch starts with the limerick
$$\begin{array}{l}\text{A Mathematician Said Who}\cr\text{Can Quote Me a Theorem that’s True?}\cr\text{For the ones that I Know}\cr\text{Are Simply not So,}\cr\text{When the Characteristic is Two!}\end{array}$$
It gives a uniform treatment of quadratic forms in all characteristics including two.
