 MAL shows more clearly than LT how closely Boole’s algebra of logic is based on Common Algebra plus the idempotent law.  The Elimination Theorem that he borrowed from common algebra turned out to be weaker than what his algebra offered, and his method of reducing equations to a single equation was clumsier than the main one used in LT, but the Expansion Theorem and Solution Theorem were the same. One sees that MAL contained not only the basic outline for LT, but also some parts fully developed. Power series were not completely abandoned in LT—they appeared, but only in a footnote (LT, p. 72).