The first printing and of Core Spell Tome 1, released simultaneously with the base game in 2012, was called Core Spell Tome, lacking the "1" that differentiated it from Core Spell Tome 2, which was released later. The numeral "1" is not present on the box of this first edition.
There are several differences between the first version and the subsequent versions:
1) The title on the box. The first edition has "Core Spell Tome" printed on all six panels. Later editions have "Core Spell Tome 1" on all six panels.
2) The spell cards inside. The first edition has the same 104 spells inside as later editions, but some of the six duplicate spells are different. The first edition contains an extra copy of Shift Enchantment and an extra copy of Jinx instead of the extra copy of Dispel and extra copy of Minor Heal found in later editions.
3) The card art for the Minor Heal spell is the original art featuring a dark-haired Priestess, matching the art found in the first edition of the base game. Later editions had the "promo card" art for Minor Heal, featuring the light-haired Priestess from the mage art.
4) The first edition has a richer, deeper color to the box and the cards inside in comparison to later printings. This coloration matches the cards from the first edition of the base game.
5) There is no "black line" or bar printing error across most of the wall conjuration cards near the bottom that appeared in later editions.