Sefer Yezirah is extant in two versions: a shorter one which appears in most editions as the book itself, and a longer version which is sometimes printed as an appendix (for the important differences between the two versions, see A. Epstein, in MGWJ, 37 (1893), 266). Both versions were already in existence in the tenth century and left their imprint on the different types of the numerous manuscripts, the earliest of which (from the 11th century?) was found in the Cairo Genizah and published by A. M. Habermann (1947). In both versions the book is divided into six chapters of mishnayot or halakhot, composed of brief statements which present the author's argument dogmatically, without any explanation or substantiation. The first chapter in particular employs a sonorous, solemn vocabulary, close to that of the Merkabah literature. Few biblical verses are quoted. Even when their wording is identical, the different arrangement of the mishnayot in the two versions and their resultant altered relationship one with the other color the theoretical appreciation of the ideas.

The central subject of Sefer Yezirah is a compact discourse on cosmology and cosmogony (a kind of ma'aseh bereshit, "act of creation," in a speculative form), outstanding for its clearly mystical character. The book's strong link with Jewish speculations concerning divine wisdom is evident from the beginning, with the declaration that G-d created the world by means of "32 secret paths of wisdom." These 32 paths, defined as "ten Sefirot beli mah" and the "22 elemental letters" of the Hebrew alphabet, are represented as the foundations of all creation. Chapter 1 deals with the Sefirot and the other five chapters with the function of the letters. Apparently the term Sefirot is used simply to mean "numbers," though in employing a new term (sefirot instead of misparim), the author seems to be alluding to metaphysical principles or to stages in the creation of the world.

Sefer Yezirah was first printed in Mantua in 1562 with the addition of several commentaries, and has since been reprinted a great many times, with and without commentaries. It was translated into Latin by the Christian mystic G. Postel and printed even before the Hebrew edition (Paris, 1552). Another Latin edition with commentaries was published by S. Rittangel in 1652. Translations appeared, mostly with commentaries, in English, by I. Kalisch (1873), A. Edersheim (1883), W. Westcott (1911), K. Stenring (1923), Akiva ben Joseph (The Book of Formation, 1970), in German by J. F. von Meyer (1830), L. Goldschmidt (1894: which, quite unfoundedly, professes to give a critical Hebrew text), E. Bischoff (1913); in French by Papus (1888), Duchess C. de Cimara (1913); in Italian by S. Savini (1923); in Hungarian by B. Tennen (1931): and in Czech by O. Griese (1921).

על שתי הנוסחאות של החיבור עיין: א' עפשטיין, מקדמוניות היהודים, ירושלים תשי"ז, עמ' רד-רי; א"מ הברמן, אבנים לחקר "ספר יצירה", סיני, כ, תש"ז, עמ' רמא-רנ. "פירוש ר' סעדיה גאון" יוחס אליו בטעות. עיין: צ' מלטר, כתבי רס"ג והספרות עליו-רב סעדיה גאון, קובץ תורני-מדעי, ירושלים תש"ג, עמ' תרד-תרו, תרלד. "פירוש ר' אליעזר מגרמישא" הוא מקוצר. הפירוש בשלימותו נדפס בפרעמישלא 1883. עיין: ג' שלום, פרקים לתולדות ספרות הקבלה, ירושלם תרצ"א, עמ' 4; א' עפשטיין, שם, עמ' ריד-רטו. "פירוש הרמב"ן" הוא פירושו של ר' עזריאל מגירונה. עיין: י' תשבי, כתבי המקובלים ר' עזרא ור' עזריאל מגירונה, סיני, טז, תש"ה, עמ' קנט. פירושו האמיתי של הרמב"ן עיין: ג' שלום, שם, עמ' 111-87. "פירוש הראב"ד" הוא פירושו של ר' יוסף ב"ר שלום האשכנזי, עיין: ג' שלום, שם, עמ' 18-2.