SAMPLE ENTRIES:

COLUMN 1 contains the tape number as cataloged in EMI's archives. The most common prefix (E) probably refers to Emitape, the in-house brand of recording tape used at Abbey Road Studios. Tapes from sessions at other studios generally have the generic prefix (AR), which probably stands for Abbey Road. Barrett usually noted the name of each non-EMI studio beneath the tape number.
     A master tape compilation used to master a single, EP, or LP has the prefix (TL), perhaps an abbreviation for "title". Master tapes usually consisted of the final mono or stereo mixes of every song on that record, spliced together from various mix reels.
     The original Barrett notes contained a sixth column, headed "ELSTREE NO." - this number (which can be seen scrawled on many of the tape boxes reproduced in Lewisohn's books) presumably refers to the tape's current location in the tape library (Beatles tapes are no longer housed at Abbey Road itself). Since the actual numbers are of no use to anyone outside of the library, I've omitted them; however all tapes without an Elstree # have brackets surrounding their number (for example [E60016]). This is important information, because it shows us which tapes are still in existence and which have been destroyed or lost. In some cases, Barrett noted the dates (mostly in 1966) when the tape was scrapped; in all other cases, the most we can assume is that the tape was missing as of 1982 and may have since been discovered from where it was misplaced.
     Thus, in the above example, we can see that the master reel for the "From Me To You" single still exists, while the mono mix tape of "She Loves You" and session tape of "Please Mr. Postman" probably do not.

COLUMN 2 tells us what type of multi-track tape is used: twin-track (2T), four-track (4T), eight-track (8T), and even three-track (3T) or twenty-four track (24T) in rare cases.
     For mixdown tapes, the symbol A (actually a Delta or triangle in Barrett's notes) indicates monophonic, Z indicates stereophonic, and Q indicates quadrophonic. For most mix tapes, Barrett also added the notation (remix), and occasionally added other comments such as (1/2") indicating a half-inch tape width.
     For master tapes, this column indicates the type of release, (S) for single, (EP) for extended play, and (LP) for long-playing record.

COLUMN 3 lists the song titles contained on each tape, with take numbers (TK), or mono (RM) or stereo (RS) mix numbers in parentheses. Various notes on the recordings are also found here, such as (O/D) for overdubs or (SI) for superimposition (these terms are synonymous). Tape reductions are notated with something similar to (4T-4T), which indicates that another four-track tape was copied over onto three or fewer tracks of this new four-track tape to make room for further overdubs.
     Tapes that were copied for various people, as well as songs that were excised from the tape for inclusion on a master reel, are often noted here. Many of the earlier recordings are keyed to "Job Numbers", which were probably for accounting purposes and merely indicated the overall project with which the session was connected.
     Master tapes have the single, EP, or LP titles followed by matrix numbers in parentheses. Singles and EP's matrices begin with (7) to indicate a 7-inch disc. (XCE) is used for mono singles, (YCE) for stereo singles (only a couple of these), and (TCE) for EP's. (XEX) indicates a mono LP, and (YEX) its stereo counterpart.

COLUMN 4 shows which takes or mixes were considered "best" from a particular session. (B) usually indicates the final take used for mixing, or the final mix used for mastering, although this doesn't always hold true. Barrett used a crossed out "B" to signify a temporary "best" take or mix; I have replaced that with a lowercase (b). Occasionally, an M (or m) is used in place of B, but the meaning is the same.
     The "best" take or mix is the last one numerically, unless otherwise noted (for example with a (TK5) next to the B), or unless two or more takes or mixes were to be edited together, usually noted with (ED).

COLUMN 5 has the dates of each recording or mix session, including sessions for overdubs. Master tapes usually have the record's release date in this column, but in later years this is often replaced by an earlier date, probably when the master tape for that release was completed.

ABBREVIATIONS AND SYMBOLS:

2T - Twin-track (or two-track) recording tape; used from the beginning through "WITH THE BEATLES"
3T - Three-track recording tape; used only for the "HOLLYWOOD BOWL" album
4T - Four-track recording tape; used from "I Want To Hold Your Hand" through "THE BEATLES" and occasionally thereafter
8T - Eight-track recording tape; used from "THE BEATLES" through "LET IT BE"
24T - Twenty-four track recording tape; used only for the "HOLLYWOOD BOWL" album
A - Monophonic mix tape
AR - Tape prefix; used for tapes recorded at studios other than Abbey Road
b - Temporary "best" take or mix, either rejected or later improved upon
B - Final "best" take used for mixing or "best" mix used for release
E - Tape prefix; used for tapes recorded at Abbey Road
ED - Editing or splicing of the tape itself or of one or more tapes together
EP - A 7-inch 45 RPM extended play record, usually with two songs per side
LP - A 12-inch 33 RPM long-playing record album
O/D - An overdub, adding new sound to an existing tape
Q - Quadrophonic mix tape; only used for a rejected release of "SGT. PEPPER"
RM - Remix from multitrack to monaural
RS - Remix from multitrack to stereo
S - A 7-inch 45 RPM single record, with one song per side
SI - Superimposition (see O/D)
TK - Take; a discrete attempt at recording a song, including false starts, breakdowns, and completed takes
Z - Stereophonic mix tape