The theories of Darwin and Wallace were similar, both seeing evolutionary change coming about as a function of a differential reproduction fueled by the pressure to succeed in the struggle for existence.  Darwin and Wallace came to their thinking independently.  The behavior of both men, in what could have been a tense situation, was exemplary.  Wallace sent his paper to Darwin, a postal journey from the Far East to England that took far longer than people expect.  This has led to beliefs that Darwin sat unfairly on the paper, perhaps using it to burnish his own work.  In truth, upon its receipt, Darwin quickly contacted his senior friends Lyell and Herschel, offering to let Wallace have full priority.  Lyell and Hooker arranged for Wallace’s paper and unaltered, pertinent abstracts of Darwin’s earlier writings to be published together in the journal of the Linnaean Society.  Both Darwin and Wallace always felt that matters had been dealt with speedily and honorably.  That said, there were significant differences in the thinking of Darwin and Wallace.  The latter was never comfortable with the metaphor of selection, he always embraced group selection in opposition to Darwin’s determined individual selectionist thinking, and most famously – notoriously – Wallace turned to spiritualism to explain human evolution, spurring Darwin to give an entirely naturalistic explanation is his Descent of Man.