Here you will find the official cocktail list by the international bartenders association. it might be your best shot at defining classics but there’s much discussion to be had. But that’s the fun of it! More on reddit.com

Elemental Mixology, by Andrew Willett is the book you're looking for. He breaks down the drink genres and the elements that make each one up, better than any book I've ever read. His technique and methodology are spot on, and his historical references are second to none. To briefly summarize, there are seven elements that go into mixed drinks: AROMATIC—bitters, spices, herbs, zests (the outer part of citrus peel), edible flowers, culinary perfumes (such as orange blossom water) SOUR—lemon juice, lime juice, vinegar, most shrubs, acid phosphate, pure cranberry juice SWEET—sugar, simple syrup, gum syrup, rock candy syrup, honey, agave nectar, maple syrup, grenadine (pomegranate) syrup, raspberry syrup, other flavored syrups STRONG—all alcoholic beverage products except petite bitters [strong products that are sweet, such as liqueurs, can also act as the sweet element] WEAK—ice, flat water, sparkling mineral water, seltzer water, soda water, fancy ‘pop’, brewed coffee, brewed tea THICK—milk, cream, eggs (including whole eggs, egg whites, egg yolks), condensed milk, butter, coconut milk, gelatin SUCCULENT—fruit and vegetables considered fit for consumption in their unsweetened state, such as orange, grapefruit, pineapple, etc. And here are the drink genres, note that there are sub-types that fall under each of the main drink genres, for example Cocktail would fall under the Sling genre, Daisy and Sour would fall under the Punch genre, etc. THOROUGHBREDS—Thoroughbreds are single strong element ingredients, generally unmixed (except perhaps with a little water or ice). EXAMPLES: Whiskey Neat, Gin "straight-up", Vodka "straight-up" ENSEMBLES—Ensembles are multiple strong element ingredients, generally unmixed (except perhaps with a little water or ice). EXAMPLES: Rusty Nail, B&B GROGS—Grogs are mixed drinks led by the weak element, in which the strong element is used as a fortifier. EXAMPLES: Irish Coffee, "Highballs"--Rum & Coke, Gin & Tonic, Vodka & Soda SLINGS—Slings are mixed drinks led by the strong element – being moderately sweetened, diluted, and usually aromatized. EXAMPLES: Manhattan Cocktail, Old Fashioned Whiskey Cocktail, Negroni Cocktail, Mint Julep, Martini Cocktail, Vesper Toddy POSSETS—Possets are mixed drinks in which the sweet, strong and thick elements are balanced. EXAMPLES: Brandy Alexander, White Russian PUNCHES—Punches are mixed drinks in which the sour, sweet, strong and weak elements are balanced. EXAMPLES: Margarita Daisy, Mojito Collins, Cosmopolitan Daisy, Long Island Iced Tea Collins, Lemon-drop Daisy, Side-car Daisy, Mai-Tai Fix, Whiskey Sour BLOSSOMS—Blossoms are mixed drinks in which the strong and succulent elements are balanced. EXAMPLES: Blinker, Blood & Sand, Brown Derby JUICE-HIGHBALLS—Juice-highballs are mixed drinks led by the succulent element, in which the strong element is used as a fortifier. EXAMPLES: Screwdriver, Salty Dog, Cape Cod So between these 7 elements and 8 drink genres, you can literally make any drink out there. And any existing drink will include at least one of those elements and fall under one of those specific genres. Learning the elements and drink genres makes it much easier to create your own drinks, as well as remember recipes. I think the current PDF edition of his 400+ page book is $7.50. Definitely worth it, if you want to get into the true DNA of what makes up a particular type of mixed-drink. More on reddit.com

Categorizing cocktails into fundamentals or families is mostly an academic exercise. It can depend on whom you read or want to believe. Employees Only breaks it down into ten ; Simon Difford into 36 ; Paul Clarke into 13 ; Gaz Regan into 20 ; Sam Ross into 5 or 6 ; everyone's favorite - European Bartender School into 8 ; etc. There is no "authoritative voice" on the subject. Just go with whatever makes sense to you and helps you learn and understand the best. More on reddit.com