A Long Important Letter by Rabbi Kook on “Ta'amei HaMitzvot”

An important unknown letter by Rabbi Avraham Yitzchak HaCohen Kook, Chief Rabbi of Israel, written to Rabbi Shimon Leib HaLevi Bamberg. London, 1925.
Five pages handwritten and signed by Rabbi Kook. Written as a recommendation for a book authored by the recipient dealing with “ta'amei hamitzvot”. Rabbi Kook extensively explains the words of Rabbi Akiva to his companions when entering the orchard: "When you reach the place of marble stones do not say water, water" and he deals with the subject of “ta'amei hamitzvot”. Included also is an explanation of the words of the Ramak in his book “Pardess Rimonim” that "620 light pillars at the end of the crown are the foundations of the Ratzon of ta'amei hamitzvot". As far as we know, this letter was never printed.
[5] pages on 3 leaves. 23 cm. Good condition, fold marks and tears to margins.