In the novel The Big Four, Abe Ryland is an extremely wealthy American industrialist. Known as the "soap king", he was reputedly the richest man in the world, "richer even than Rockefeller".
At the beginning of the novel, Ryland had offered Poirot a commission to investigate a problem with one of his companies in Rio de Janeiro. Although Poirot disliked long ocean voyages and at firs refused, he confessed to Hastings that "the sum offered was so stupendous that for the first and last time in my life I was tempted by mere money." Poirot was, however, interrupted by the events in The Unexpected Guest.
As Poirot proceeded in his investigation in the “Big Four” conspiracy, he surmised that Ryland was actually “Number Two”, and the financial muscle behind the crime syndicate. The offer to Poirot was merely to get him out of the way.
This was confirmed when Hastings managed to infiltrate Rylands staff and become his English social secretary in In the House of the Enemy. Hasting took up his duties at Hatton Chase, Ryland's rented country house under the cover name of Major Neville. However the job turned out to be a trap to lure Hastings and, through him, Poirot, to a remote quarry to murder them. Poirot had seen through this and arranged for Scotland Yard men to surround the place. However when they arrested Ryland in the quarry, it turned out to be James, Ryland's footman, disguised as his employer. Nonetheless, Poirot was satisfied with the outcome. He had confirmed that Ryland was "Number 2" and that James was likely to be the master of disguise and chief hitman of the group, "Number 4".
Ryland was killed at the end of the novel when in The Crag in the Dolomites, the chiefs of the "Big Four" had gathered in their mountain headquarters at Lago di Carezza only to find that Poirot had arranged for the place to be surrounded by police. Rather than surrender, the members of the "Big Four" chose to kill themselves in a massive explosion which also destroyed their hideout.
Hastings described Ryland as an impressive man, "tall and lean, with a jutting out chin and slightly hooked nose. His eyes glittered cold and grey behind penthouse brows. He had thick, grizzled hair, and a long black cigar ... portruded rakishly from the corner of his mouth."