Perhaps the strongest Austrian-born grandmaster of the20th century, Rudolf Spielmann (1883–1942) defeated such world-class opponents as Nimzovich, Tartakower, Bogoljubov — and even the great Capablanca. Among the reasons for his success was his mastery of the art of sacrifice. In this ground-breaking classic, distilled from 40 years of tournament play, he outlines the hard-won lessons that enable a player to win games by giving up pieces! Drawing on dozens of his own games against such topflight players as Schlechter, Tartakower, Bogoljubov, Reti, Rubinstein and Tarrasch, Spielmann describes and analysis various type of sacrifices: (positional, for gain, mating) and real sacrifices: (for development, obstructive, preventive, line-clearance, vacating, deflecting and more). The result was the first systematic attempt to explain and exploit the theory of chess sacrifice; it remains an extremely helpful and useful weapon in the arsenal of chess players at every level
Interesting games, but Spielmann tends to bog down in vague considerations not grounded in concrete analysis. Also, he seriously overestimates the attacker's chances in many positions, and several times this irretrievably mars otherwise sound analysis.
It's probably best to look upon this as a games collection rather than a textbook. There are indeed some great games here (I particularly liked that one against Bogoljubov where Spielmann's queen ends up on b1). As an instructional manual it's not of terribly much use: just some tedious discussions of classification and whatnot, during which Rudy unfortunately manages to indulge his penchant for being very pedantic indeed.