嘉慶十三年戊辰（1808年）曉樓三十四歲刊刻生平的第一本書《四書典故覈》，前有洪梧、貴徵及曉樓自序，凌曙〈四書典故覈自敘〉曰：「甲子之秋，曙齒且及壯，得識安吳包君慎伯。過從請益，極承勸誘。嘗言吾人為學，自治經始。治經自三禮始......欲治三禮者，當先精制義之法，制義依四子書以立言。」又言：「丙寅春，曙遂隨包君至申耆先生家，親承指授。筆記其略，歸按之于籍，始知其言之有旨、辨之非夸。紬繹既久，漸能錯綜推廣其意。乃就四子書之舊次，編輯為《典故覈》若干卷。」凌曉樓學術之次第，以張惠言《四子書漢說》為階梯，而窮究《四書》之典章、名物。尤其引《三禮》、《春秋》以明《四書》之禮制，以經解經駁斥學者之憑空臆說。又由《四書》進而精研《三禮》，以鄭玄《儀禮注》為裁斷諸說之的，著《禮論略鈔》、《儀禮禮服通釋》。同時著《春秋繁露注》以通《春秋》，以董仲舒《春秋繁露》為《公羊傳》之真傳，成《公羊禮疏》、《公羊問答》、《公羊禮說》以成一家之言。凌曉樓之《公羊》學，不以辨章義理為務。然透過禮制之考求，而孔子微言大義自明於前。曉樓之作《四書典故覈》專以典章、禮制之考據為主。以為此典章備，則聖人治天下之理亦備。並指朱子《四書集註》亦蔽於典章、名物之說，為其瑕疵。貴徵之〈序〉以「冀義理、典章兩無遺闕」為說，並提出「今之讀《四子書》者，亦當以經解經」的呼籲。而「以經解經」正是曉樓《四書典故覈》所堅持的原則，曉樓據此原則以探求《四書》、《三禮》、《春秋經、傳》間的關連，開創以《三禮》為樞紐以解群經的治經之法。

Ling-xiao-low order of academy, inquiry about ”the Si-Shu” ”speech” four philosophical works Chinese say ”as ladder, institutions, famous things to make a thorough inquiry about” the Si-Shu”. ”Especially guide”san-li three sceremony”, ”chun-qiu” with the rites system of bright ”the Si-Shu”, in order to be solved by the assumption without foundation which refutes the scholar. And then precise to grind ”san-li three sceremony” by ”the Si-Shu”, with profound ”appearance rites note” Zheng-Nuan for decide ones that say, ”slightly in rites theory for sketchy note”, ”whether it is the coherent to clear up in full dress in rites At the same time” whether chun-qiu the in great numbers to reveal by note” by ”chun-qiu” scoherent, by Dong Zheng-Nuan” it is the in great numbers to reveal by ”for the not handing down in a direct line from the master of ”biography Gongyang” ”Chun-Qiu,”whether dredge Gongyang rites”, ”question and answer Gongyang”, ”last ”in order to becoming rites Gongyang by statements of a school.” Ling XiaoLou's” buck” studies, does not regard distinguishing Zheng-nuan Yi-Li as the affair. But take an exam of asking through what the rites is made, and self-evident Yu Qian of the main idea of Confucius'main points.